Anatomy - the study of the structure of body parts & their relationship to one another
a. Gross (Macroscopic) Anatomy – the study of large (readily visible) body structures (heart, lungs, kidneys)
b. Microanatomy – the study of microscopic body structures; Cytology is the study of cells & Histology is the study of tissues
c. Regional Anatomy – the study of groups of structures in specific body regions
d. Systemic Anatomy – the gross anatomy of organ systems is studied
e. Surface Anatomy – the study of internal body structures as they relate to the body surface (skin)
Physiology - the study of the function of the body¹s structural machinery
Negative Feedback: the product or response shuts off or reduces the level of the original stimulus; the variable then changes in a direction opposite the initial change
Examples of negative feedback mechanisms: regulation of body temperature, the withdrawal reflex, regulation of blood glucose levels by the hormones insulin & glucagon
Serous membranes: thin 2-layered membranes with fluid-filled space that covers the viscera within thoracic & abdominal cavities and lines walls of thorax & abdomen
- 2 layers:
o visceral layer: covers & adheres to organs within cavity
o parietal layer: lines walls of cavity
- Pleura: covers lungs within pleural cavities
- Pericardium: covers heart within pericardial cavity
- Peritoneum: covers abdominal viscera within abdominal cavity
Know the location of each of the following. Also know the subdivisions where appropriate (for example: the pleural cavity is within the thoracic cavity, which in turn is within the ventral body cavity).
Dorsal Body Cavity
- Cranial cavity
- Vertebral or Spinal cavity
Ventral Body Cavity
- Thoracic cavity
o Pleural cavity
o Mediastinum
o Pericardial cavity
- Abdominopelvic cavity
o Abdominal cavity
o Pelvic cavity
Abdominopelvic Quadrants
Energy – the capacity to do work
- Potential energy: stored energy that is available to do work
- Kinetic energy: energy of motion
Forms of energy:
Chemical energy – energy in the bonds of chemicals
Electrical energy – energy in the movement of charged particles
Mechanical energy – energy used directly to move matter (used by muscle cells)
Radiant energy – energy that travels in waves (includes solar energy, light energy)
Chemical Reactions:
Oxidation: loss of electrons or H atoms
Reduction: gain of electrons or H atoms
Exergonic reactions: release energy
Endergonic reactions: require (absorb) energy
The rate of a chemical reaction is influenced by:
1. temperature: molecules move faster as the temperature is increased (increases collisions)Š moderate temperature is best; high temperatures often denature (inactivate) enzymes
2. particle size: small molecules move faster (more (forceful) collisions)
3. concentration: usually increased reactant concentrations increases rate (more collisions)
4. catalysts: increase rate of chemical reactions without themselves being changed in the reactionŠ enzymes are biological catalysts
Biochemistry:
Organic Molecules: Carbon-based molecules
Inorganic Molecules: Molecules that do not contain carbon and hydrogen (e.g.: salts, strong acids and bases, metal compounds)
Carbohydrates: (contain carbon, hydrogen, and oxygen atoms)
Monosaccharides: simple sugars with a backbone of 3 to 7 carbon atoms
Disaccharides: 2 monosaccharides joined by condensation
Polysaccharides include:
- Starch is a more moderately branched polymer of glucose, and is the storage form of carbohydrates in plant cells
- Cellulose is an unbranched polymer of glucose, with adjacent chains held together by hydrogen bonds, giving it a very rigid structure. It is the major structural component of plant cell walls
Lipids:
In the form of neutral fats (fats or oils)
One triglyceride = Glycerol + 3 fatty acids
Proteins:
Proteins are composed of chains of amino acid monomers
- Each amino acid has a central carbon bonded to an amino group, a carboxylic acid group, a hydrogen atom, and the remaining side chain (R group); it is the R group that differs in different amino acids
- the R groups do not normally bond between amino acids (the exception is cysteine, which forms disulfide (S-S) bonds within and between polypeptide chains for added strength
Denaturation: disruption of specific 3D structure of a protein by increasing temperature (boiling) or changing pH
Nucleic Acids:
Nucleic Acids are polymers of nucleotide monomers
- a nucleotide = a pentose sugar + a phosphate + a nitrogenous (nitrogen-containing) base
DNA:
DNA is the genetic material of the cell (inherited from parents)
- Composed of a sequence of four different nucleotides
- The 4 nucleotide subunits of DNA are named after the nitrogenous base each
contains; the 4 bases are : adenine (A), cytosine (C), guanine (G), & thymine (T)
- Adenine and Guanine are purine bases, and have very similar structures
- Cytosine and Thymine are pyrimidine bases, and have very similar structures
- DNA forms a double-helical structure (DNA is double-stranded)
- The 2 strands (nucleotide chains) of the double helix are complementary:
each base always pairs with its complement, so that the second strand of the double helix can be deduced, and synthesized in the cell, by simply pairing complementary bases
RNA:
- RNA is synthesized from 1 strand of DNA
- RNA does not form a double helix (no pairing of complementary bases between 2 strands); RNA is single-stranded
- RNA also uses 4 nucleotide subunits; however, uracil (U) replaces thymine in RNA
Chapter 3: Cells: The Living Units
Outer boundary of cells:
Plasma membrane: outer boundary of cells (except plant cells – also cell wall)
- phospholipid bilayer: semipermeable and selectively permeable
- functions in regulation of passage of molecules into and out of the cell
Facilitated Diffusion: passage of small molecules (glucose, amino acids) across the plasma membrane even though they may not be lipid-soluble
- a carrier protein assists movement of molecules down concentration gradient
- no energy is required
Filtration: a pressure gradient pushes solute-containing fluid (filtrate) from area of high pressure to area of low pressure
Cell adhesion molecules (CAMs): anchor cells to extracellular space & each other
- used by cells to assist in migration & recruit immune cells to sites of infection/injury
Cytosol:
Cytoskeleton: composed of microtubules, intermediate filaments, and actin filaments
- Functions in maintaining shape of cell and movement of subcellular structures
- Microtubules: composed of tubulin dimers coiled into tubelike structures
- Intermediate Filaments and actin filaments have structural roles throughout the cell
- Actin filaments combine with myosin in muscle cells to enable muscle movement
Endoplasmic Reticulum: (ER)
- Rough ER: associated with ribosomes; proteins translated on ribosomes associated with the rough ER will be transported and/or secreted outside cell
- Smooth ER: synthesizes phospholipids in all cells; various other cell type-specific functions
Microbodies: smaller version of lysosomes with specific enzyme activities
- Peroxisomes are microbodies that contain enzymes for oxidizing certain organic molecules with the release of hydrogen peroxide (toxic, but breaks down into water & oxygen)
Nucleus: stores genetic information in all eukaryotic cells
- DNA is organized into distinct chromosomes
- Within each nucleolus, ribosomal RNA is produced and joins with ribosomal proteins to form ribosomes
- The nucleus is bounded by a porous membrane, the nuclear envelope, which regulates passage of molecules into & out of the nucleus
Cell Division:
Cell Cycle: Consists of Interphase and Mitosis
Interphase: consists of G1, S, and G2 stages.
- S phase is the synthesis stage of the cell cycle, when the DNA is replicated.
- G1 stage is a growth (formerly gap) stage during which the organelles increase in number to produce enough for two new cells
- G2 stage is also a growth stage in which metabolism provides new metabolites and energy for the mitotic division
DNA Synthesis
DNA replication is carried out by the enzyme DNA Polymerase, as well as some additional protein factors
Mitosis: M stage
Prophase: chromatin condenses and the nuclear membrane begins disintegration. Mitotic spindle begins to assemble from microtubules in centrosomes, where centrioles form short asters prior to formation of spindle fibers.
Late Prophase: chromosomes attach to the spindle fibers, and are moved toward the center of the cell (metaphase plate). Spindle fibers attach to the kinetochores (attachment point of centromeres) of duplicated chromosomes. Nuclear membrane completes disintegration.
Metaphase: Chromosomes align at metaphase plate attached to kinetochore spindle fibers
Anaphase: Chromosomes move toward opposite poles of the cell due to disassembly of spindle fibers
Telophase: Chromosomes are at opposite poles of the cell; nuclear envelope reforms around each set of chromosomes, and spindle disappears. Cytokinesis beginsŠ
Cytokinesis:
- Animal cells divide by means of a cleavage furrow
- Plant cells divide using a cell plate to allow formation of a new plasma membrane and cell wall between the two new cells. Cell wall is too rigid for cleavage furrow
Gene Expression:
- DNA is transcribed to RNA in the nucleus
- transcription is carried out by a 5¹ to 3¹ RNA Polymerase, as well as additional protein factors
- the result of these modifications is mature mRNA
- Mature mRNA is translated to protein in the cytoplasm (at the ribosomes)
- tRNA molecules carry amino acids to the ribosome during translation (a tRNA for each amino acid)
- rRNA along with proteins comprise the structure of the 2 subunits of the ribosome
Chapter 4: Tissue: The Living Fabric
Epithelial Tissue (epithelium): a sheet of cells that lines a body cavity or covers a body surface
Simple Squamous Epithelial Tissue: single layer of flattened cells with disc-shaped nuclei & little cytoplasm
- locations: in kidney glomeruli, air sacs of lungs, heart lining, blood vessels & lymphatic vessels, lining of ventral body cavity
- functions: diffusion & filtration; secretes lubricating substances in serosae
Simple Cuboidal Epithelial Tissue: single layer of cube-shaped cells with large spherical nuclei
- locations: in kidney tubules, ducts of small glands, ovary surface
- functions: secretion & absorption
Simple Columnar Epithelial Tissue: single layer of column-shaped cells with oval nuclei; some have cilia or microvilli; may include goblet cells
- locations: nonciliated in most of digestive tract, gallbladder & excretory ducts of some glands; ciliated in small bronchi, some regions of uterus
- functions: absorption, secretion of mucus, enzymesŠ; ciliated propels mucus, reproductive cells
Pseudostratified Columnar Epithelial Tissue: single layer of mostly column-shaped cells with different heights (some don¹t reach apical surface) & nuclei at different levels; some have cilia; may include goblet cells
- locations: nonciliated in male sperm-carrying ducts & ducts of large glands; ciliated type lines trachea & most of upper respiratory tract
- functions: secretion & propulsion of mucus
Stratified Squamous Epithelial Tissue: multiple layers; basal layer cuboidal or columnar – carry out metabolism & mitosis; outer layers are keratinized
- locations: nonkeratinized type forms linings of esophagus, mouth & vagina; keratinized type forms epidermis of skin
- functions: protects underlying tissues
Stratified Columnar Epithelial Tissue: several layers – basal layer usually cuboidal
- locations: male urethra & some large ducts of glands
- functions: protection, secretion
Transitional Epithelial Tissue: several layers – basal layer cuboidal or columnar; surface cells dome-shaped or squamous-like (depending on stretch)
- locations: ureters, bladder & part of urethra
- functions: stretches & distends urinary organ
Connective Tissue: most abundant primary tissue
- extracellular matrix (collagen or elastin fibers; calcium phosphate (bone)
Ground Substance: fills space between cells & contains fibers
- composed of interstitial fluid, cell adhesion proteins & proteoglycans
Connective Tissue Types:
Areolar Connective Tissue: gel-like matrix with all 3 fiber types; fibroblasts, mast cells, macrophages & some white blood cells
- location: under many epithelia (forms lamina propria); around organs & capillaries
- functions: cushions organs; many immune cells regulate immunity
Adipose Connective Tissue: closely packed adipocytes (fat cells with large fat droplet)
- location: under skin, around kidneys & eyeballs, within abdomen, breasts
- functions: cushions organs; reserve food fuel, insulation
Reticular Connective Tissue: reticular fiber network in loose ground substance; reticular cells
- location: lymphoid organs
- functions: internal skeleton for support of other cell types
Dense Regular Connective Tissue: dense (primarily) parallel collagen fibers, few elastin fibers; fibroblasts
- location: tendons, ligaments, aponeuroses
- functions: attaches muscles to bone & other muscles, attaches bones to bones; withstands high stress
Dense Irregular Connective Tissue: irregular shaped collagen fibers, few elastin fibers; fibroblasts
- location: dermis of skin, digestive submucosa, fibrous capsules of organs & joints
- functions: withstands tension, adds structural strength
Hyaline Cartilage: amorphous firm matrix; collagen fibers form glassy (invisible) network; chondrocytes in lacunae
- location: embryonic skeleton, covers long bones in joints, costal cartilage of ribs, cartilage of nose, trachea & larynx
- functions: support, cushioning, resists stress
Elastic Cartilage: similar to hyaline cartilage, with elastin fibers in matrix
- location: external ear (pinna), epiglottis
- functions: maintains shape while adding flexibility
Fibrocartilage: similar to hyaline cartilage, less firm with thick collagen fibers in matrix
- location: intervertebral discs, pubic symphysis, knee joint discs
- functions: tensile strength, absorbs shock
Bone: hard calcified matrix, many collagen fibers, well vascularized, osteocytes in lacunae
- location: bones
- functions: support, levers for muscles, calcium storage, blood cell formation (hematopoiesis) in marrow
Blood: red blood cells (erythrocytes) & white blood cells (leukocytes) in fluid matrix (plasma)
- location: in blood vessels
- functions: transports oxygen & carbon dioxide, nutrients, wastes & other substances
Nervous Tissue: neurons & supporting cells
- location: brain, spinal cord & nerves
- functions: transmit electrical signals from sensory receptors to effectors
The Skin (Integument): composed of 2 regions:
- Epidermis: outermost layer composed of epithelial cells
- Dermis: underlying layer composed of fibrous connective tissue; vascularized
Hypodermis: subcutaneous layer just deep to the dermis
- mostly adipose with some areolar connective tissue
- insulates, absorbs shocks, & anchors skin loosely to muscles
Epidermis: keratinized stratified squamous epithelium
- 4 distinct cell types:
o keratinocytes: produce the fibrous protein keratin
§ tightly connected by desmosomes
§ outermost cells dead & keratinized; lifespan of 25-45 days
§ thick skin has accelerated cell division & keratinization
o melanocytes: spider-shaped cells that produce the pigment melanin
§ located in deepest layer of epidermis; melanosomes in melanocyte processes transfer melanin to keratinocytes
§ melanin granules protect the cell nucleus from UV radiation
o Langerhans¹ cells (epidermal dendritic cells): macrophages; part of immune system
§ produced in bone marrow; migrate to epidermis & form network around keratinocytes
o Merkel cells: associate with disclike sensory nerve endings to form Merkel disc – a sensory receptor for touch
Layers of Epidermis:
- Thick skin has 5 layers (strata)
o Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum & stratum corneum
- Thin skin has only 4 layersŠ missing stratum lucidum; stratum corneum thinner
Stratum Basale (Stratum Germinativum): basal layer; deepest epidermal layer firmly attached to dermis
- single layer of cells; cell division produces new keratinocytes for all layers
Stratum Spinosum: several layers thick; interrupted by dermal papillae
- keratinocytes are flat & spiny (prickle cells)
- some melanin granules; Langerhans¹ cells
Stratum Granulosum: 3-5 cell layers thick; cells contain granules
- keratohyaline granules: help in keratin formation
- lamellated granules: contain waterproofing glycolipid – released into extracellular space to prevent water loss
Stratum Lucidum: a few rows of clear, flat dead keratinocytes
- only in thick skin
Stratum Corneum: outermost layer; 20-30 cell layers thick
- protects skin with keratin & thick plasma membranes; glycolipids prevent water loss
Dermis: strong, flexible connective tissue
- fibroblasts, macrophages, mast cells & white blood cells with collagen, elastin & reticular fibers
- rich supply of nerve fibers, blood vessels & lymphatic vessels
- houses hair follicles, oil & sweat (sudoriferous) glands
- papillary layer: upper layer composed of areolar connective tissue
o dermal papillae: projections that indent the epidermis; contain capillary loops & touch receptors (Meissner¹s corpuscles)
o dermal ridges on palms of hand & soles of feet form epidermal ridges – genetically determined pattern of ridges; leaves fingerprint
- reticular layer: lower layer (most of thickness of dermis); composed of dense irregular connective tissue
o thick collagen fiber bundles form lines of cleavage (tension lines) in skin; used in surgery (incisions made parallel to lines to speed healing)
o flexure lines: dermal folds near joints
Skin Color: dictated by 3 pigments: melanin, carotene, & hemoglobin
- melanin: tyrosine polymer; relies on enzyme tyrosinase in melanocytes
o protects cell nucleus from UV light-induced mutations; UV repair mechanisms may stimulate synthesis
- carotene: yellow-orange pigment found in plants (carrotsŠ)
o accumulates in stratum corneum & hypodermis; most evident in thick skin
- hemoglobin: oxygenated hemoglobin in dermal capillaries gives fair skin a pinkish color
Skin Appendages:
Sweat (sudoriferous) glands: eccrine & apocrine
- eccrine sweat glands (merocrine sweat glands): far more numerous – most abundant on palms of hands, soles of feet & forehead
o secrete sweat: hypotonic blood filtrateŠ 99% water with salts, vitamin C, antibodies, metabolic wastes & lactic acid
o sweat prevents overheating; regulated by sympathetic division of autonomic nervous system
- apocrine sweat glands: mostly confined to axillary & anogenital regions
o ducts empty into hair follicles
o in addition to components of sweat, secretion contains lipid & proteins
- ceruminous glands: modified apocrine glands in the external ear canal
o secrete cerumen (earwax); deters insects & blocks foreign material
Sebaceous (oil) glands: simple alveolar glands (holocrine glands); located all over body except palms of hand & soles of feet
- secrete sebum (rich in oils) into hair follicle (or pore)Š bacteriocidal; lubricates hair & skin
- inflammation/infection can lead to acne; overactivity leads to seborrhea
Hair & hair follicles:
- hair (pili) are flexible strands of mostly dead, keratinized cells
- melanin from melanocytes at base of follicle produces color
- hair follicle: extends from epidermal surface to dermis or hypodermis
o arrector pili muscle: smooth muscle bundle that contracts to raise hair
- types of hairs: short, fine vellus hairs; longer, coarser terminal hair
- alopecia: hair loss brought on by aging & hormones
Nails: scalelike epidermal modifications at dorsal surface of distal region of fingers & toes
- nail matrix cells produce new growth
- meet skin at folds of skin called nail folds & cuticle
Bone structure:
Gross anatomy of long bones:
- Compact bone: dense outer layer of bone
- Spongy bone (cancellous bone): trabeculae – needle-like or flat pieces internal to compact bone; spaces between trabeculae filled with red or yellow bone marrow
- Diaphysis (shaft): forms long axis of bone; thick collar of compact bone surrounding medullary (marrow) cavity
o In adults, marrow cavity contains fat – yellow bone marrow cavity
- Epiphyses: ends of bone; often more expanded than diaphysis; outer compact & internal spongy bone
- Membranes: periosteum covers entire surface of bone except joint surfaces;
o endosteum: covers trabeculae of spongy bone & canals of compact bone
Hematopoietic tissue in bones:
- Hematopoiesis occurs in red marrow (in cavities of spongy bone of long bones & diploe of flat bones)
- In infants, medullary cavity & all spongy bone have red bone marrow
- In adults, red bone marrow in the head of the femur & humerus, & diploe of flat bones & some irregular bones (hip bone)
- During anemia (blood cell deficiency), yellow marrow can revert to red marrow
Microscopic structure of bone:
Compact bone (lamellar bone): units called osteons or Haversian systems
- osteons: cylinder oriented parallel to long axis of bone; within each cylinder is tubes (concentric circles) of bone matrix (lamellae)
- central (Haversian) canal: runs through center of osteon; carries blood vessels & nerve fibers
- perforating (Volkmann¹s) canal: at right angles to long axis; connect blood vessels & nerves of periosteum to those of central canals & medullary cavity
- osteocytes: bone cells in small cavities called lacunae
- canaliculi: connect lacunae to each other & central canal
- interstitial lamellae: partially formedŠ fill gaps or have been replaced
- circumferential lamellae: extend around all osteons within shaft (just deep to periosteum)
Spongy bone: trabeculaeŠ a few cell layers of irregularly arranged lamellae & osteocytes connected by canaliculi
- no osteons; nutrients delivered by capillaries in endosteum
Chemical composition of bone:
- organic component: cells (osteocytes, osteoblasts & osteoclasts) & osteoid (organic matrixŠ ground substance & collagen fibers)
- inorganic component: hydroxyapatites (mineral salts); mostly calcium phosphates
- calcium salt crystals pack around collagen fibers in matrix
Control of Remodeling:
Hormonal control:
- parathyroid hormone (PTH, from parathyroid gland): stimulates osteoclasts to resorb bone to raise blood calcium levels
- calcitonin (from parafollicular (C) cells of thyroid): inhibits osteoclasts & stimulates calcification of bone matrix to lower blood calcium levels
Osteomalacia: bones are inadequately mineralized (osteoid not calcified)
- symptoms: pain when weight placed on bones
- cause: insufficient dietary calcium or vitamin D (helps to absorb dietary calcium from intestine)
- treatment: calcium & vitamin D supplements & sunlight
Osteoporosis: bone resorption outpaces bone deposit
- normal bone matrix composition, but bone mass is reduced & bones are porous
- causes: many, including hormonal deficiencies (especially steroid hormone deficiency due to decline in old age), insufficient exercise, poor diet,Š
- treatment: calcium & vitamin D supplement, & hormone replacement therapy (HRT)
Paget¹s disease: excessive bone formation & breakdown
- Pagetic bone : abnormally high ratio of spongy bone to compact bone
- symptoms: progressive weakening & deformity of bones (esp. spine, pelvis, femur & skull)
- cause: unknown, may be viral
- treatment: calcitonin & drug therapy to prevent bone breakdown
Chapter 7: The Skeletal System
- consists of bones arranged along (longitudinal) axis of body
- includes: skull bones, auditory ossicles (ear bones), hyoid bone, ribs, sternum (breastbone) & vertebral column (backbone)
- consists of the bones of the upper & lower limbs (extremities), & the bones forming the pectoral & pelvic girdles (shoulder & hip bones) that connect the limbs to the axial skeleton
Bone Types:
- long bones: have greater length than width; consist of diaphysis (shaft) & epiphyses; slightly curved to absorb stress
o includes: femur, tibia & fibula, humerus, radius & ulna & phalanges of fingers & toes
- short bones: cube-shaped; spongy bone with thin outer layer of compact bone
o includes: carpal (wrist) bones (except pisiform, which is a sesamoid bone) & tarsal (ankle) bones (except calcaneus, which is an irregular bone)
- flat bones: thin; composed of 2 parallel plates of compact bone enclosing a layer of spongy bone
o offer protection & broad surface for muscle attachment (tendons)
o includes: cranial bones, sternum & ribs, & scapulae (shoulder blades)
- irregular bones: complex shapes; don¹t fit into other categories
o includes: vertebrae, coxal (hip) bone, calcaneus (heel bone), & some facial bones
- sesamoid bones: sesame shaped bones that develop in tendons to protect against friction & stress
o includes patellae (kneecaps) & pisiform (smallest wrist bone)
- sutural bones: small bones located within immoveable joints (sutures)
o vary in number among individuals & not included in named bones
- Know the bones & featuresŠ including basic locations for each & placing features with correct bones
Classification of Joints:
- Functional Classification:
o Synarthroses: immovable joints (suturesŠ)
o Amphiarthroses: slightly movable joints (symphysesŠ)
o Diarthroses: freely movable joints (most joints)
Fibrous Joints: bones joined by fibrous tissue; no joint cavity
- most are immovable or slightly movable
- sutures: between bones of the skull
o joined with short connective tissue fibersŠ in middle age, connective tissue ossifies forming synostoses
- syndesmoses: bones connected by ligament; immovable or slightly movable
o examples include connections between bones of lower arm (radius & ulna) & lower leg (tibia & fibula)
- gomphoses: peg in socket joint; only example is tooth in bony alveolar socket
o connected by short periodontal ligament
Cartilagenous Joints: bones joined by cartilage; no joint cavity
- synchondroses: bones joined by hyaline cartilage; almost always synarthrotic
o examples are epiphyseal plates in long bones of children, joint between costal cartilage of first rib & manubrium of sternum
- symphyses: articular surfaces of bone covered with hyaline cartilage fused to plate of fibrocartilage
o fibrocartilage compressible – shock absorber, but limited movement; joints are amphiarthrotic
o examples are intervertebral joints (discs) & pubic symphysis
Synovial Joints: bones separated by fluid-containing joint cavity
- all are freely movable
- rich supply of blood vessels & nerve endings (sense stretch)
- articular cartilage: hyaline cartilage protects bone ends
- joint (synovial) cavity: potential space with synovial fluid
- articular capsule: external fibrous capsule (dense irregular CT) & internal synovial membrane (loose CT)
- synovial fluid: occupies free spaces in joint cavity; reduces friction
o mostly blood filtrate; viscous fluid containing hyaluronic acid
o weeping lubrication: fluid forced from cartilage during compression & soaked back up when pressure is relieved
Angular movements: increase or decrease angle between 2 bones
- Flexion: decreases angle of joint & brings bones closer together
- Extension: increases angle of joint & moves bones away from each other
o Hyperextension: moving head backwards beyond straight
- Dorsiflexion: lifting foot
- Plantar flexion: depressing foot
- Abduction: movement of limb away from midline
- Adduction: movement of limb toward midline
- Circumduction: moving a limb so that it describes a cone in space
Rotation: turning of bone around its long axis
Types of Synovial Joints:
Plane Joints: flat articular surfaces, allow only short slipping or gliding movements (example: joints between vertebral articular processes)
Hinge Joints: cylindrical projection of one bone fits into trough-shaped surface on another (example: interphylangeal joints)
Pivot Joints: rounded end of one bone protrudes into a bony ring/sleeve on another (example: atlas & axis articulation)
Condyloid (Ellipsoidal) Joints: oval articular surfaces of one bone fit into depression of another (example: radiocarpal joints)
Saddle Joints: resemble condyloid joints; each bone has concave & convex articular surfaces (like saddle); greater freedom of movement (example: carpometacarpal joints)
Ball & Socket Joints: spherical (ball-shaped) head of one bone fits into cuplike socket of another (example: shoulder & hip joints)
Muscle Types:
Skeletal muscle tissue: attach to & cover bony skeleton
- longest of muscle types; striated; under voluntary control
Cardiac muscle tissue: occurs only in walls of heart
- striated; involuntary
- pacemaker cells set rate of contraction
Smooth muscle tissue: occurs in walls of visceral organs (stomach, bladder), respiratory passageways & blood vessels
- forces fluids & other substances through body channels
- nonstriated; involuntary
- slow & sustained contractions
Microscopic Anatomy of Skeletal Muscle:
- skeletal muscle cells long (hundreds of cm) & wide; multinucleate
- sarcolemma: plasma membrane of muscle
- sarcoplasm: like cytoplasm of normal cell; contains many glycosomes (store glycogen) & myoglobin (carries & stores oxygen)
- myofibrils: contractile elements of skeletal muscle
o composed of thin filaments (actin, tropomyosin & troponin complex) & thick filaments (myosin)
o myosin composed of long central tails & laterally oriented heads (cross-bridges) that bind actin
o tropomyosin covers myosin binding sites on actin molecules in resting muscle
o troponin complex consists of: TnI (inhibits actin), TnT (binds tropomyosin & positions it on actin) & TnC (binds calcium to start contraction)
o striations result from alternating dark A bands (thick filaments with overlapping thin filaments) & I bands (thin filaments) with central Z disc (connexin protein)
o A sarcomere is the region of a myofibril between adjacent Z discs
- sarcoplasmic reticulum: smooth ER of muscle cells; store calcium
Contraction of Skeletal Muscle Fiber: activation of myosin¹s cross bridges
- sliding filament mechanism: during contraction, the thin filaments slide past the thick filaments so that actin & myosin overlap to a greater degree
- nerve impulse leads to depolarization & calcium release from sarcoplasmic reticulum
- calcium binds to TnC, which changes shape & moves tropomyosin away from myosin binding sites on actin
- with myosin binding sites accessible on actin, activated myosin heads bind actin (cross bridge attachment)
- as myosin heads bind actin, they pivot as they change from high-energy shape to low-energy shape, pulling thin filament toward center of sarcomere
o ADP & P are released from myosin head
Isotonic contractions: muscle changes in length & moves load
Isometric contractions: muscle neither shortens nor lengthens
- example: muscle attempts to move a load requiring force greater than available
Muscle metabolism: muscles need constant supply of ATP
ATP Sources:
- Direct phosphorylation: creatine phosphate converted to creatine by creatine kinaseŠ phosphate released added to ADP to form ATP
- Anaerobic glycolysis & lactic acid formation: 2 ATP yield per glucose
o Lactic acid build up in muscles – causes fatigue
o Oxygen debt: need additional oxygen to oxidize & remove lactic acid from muscle cells
- Aerobic respiration: yields 36 or 38 ATP per glucose
- Know muscle locations & very general action for muscles
Organization of the Nervous System
Central Nervous System (CNS): brain & spinal cord
Peripheral Nervous System (PNS): nerves that extend from the CNS (outside the CNS)
- Sensory (afferent) division: nerves that convey impulses to the CNS from sensory receptors
o sensory neurons link body parts to CNS
o somatic afferent fibers: convey impulses from skin, skeletal muscles & joints
o visceral afferent fibers: convey impulses from visceral organs (organs of ventral body cavity)
- Motor (efferent) division: transmits impulses from the CNS to effector organs (muscles & glands)
o motor neurons activate muscle contraction & glandular secretion
o somatic nervous system (voluntary nervous system): somatic motor neurons that conduct impulses from the CNS to skeletal muscles
o autonomic nervous system (ANSŠ also involuntary nervous system): visceral motor neurons that regulate activity of smooth muscle, cardiac muscle & glands
§ sympathetic division: mobilizes body systems (accelerates circulatory & respiratory systems, slows digestion) during emergency
§ parasympathetic division: generally opposite of sympathetic responsesŠ conserves energy, promotes nonemergency functions (digestion)
Neuroglia of CNS:
- astrocytes: star-shaped; most abundant & versatile glial cells
o anchor neurons to capillaries & aid in exchange & permeability
o control chemical environment surrounding neurons – clean up potassium ions & neurotransmitters
- microglia: small ovoid cells with long ³thorny² processes that contact neurons
o can transform into phagocytic cells & engulf/break down bacteria & cell debris
- ependymal cells: shape varies from squamous to columnar; many are ciliated
o line central cavities of brain & spinal cord, between tissue fluid of interneuronal space & cerebrospinal fluid (CSF) within cavities
o cilia circulate CSF (CSF is secreted by capillaries of choroids plexuses
- oligodendrocytes: wrap processes around thicker neurons of CNS – produce myelin sheath of CNS neurons
Neurons:
- cell body (perikaryon or soma): contains nucleus & most organelles (no centrioles)
o Nissl bodies (chromatophilic substance): rough ER of neuron
o neurofibrils: bundles of intermediate filaments (neurofilaments) – maintain shape
o pigments: melanin (black), red iron-containing pigment & lipofuscin
§ lipofuscin called aging pigment (accumulates in elderly)
- processes: dendrites & axons; extend from cell body
- myelin sheath & neurilemma: myelin sheath (whitish protein-lipoid segmented sheath) formed by oligodendrocytes in CNS & Schwann cells in PNS – cells wrap themselves around axon of neuron
o myelinated fibers conduct impulses rapidly; unmyelinated fibers conduct impulses slowly
o neurilemma: bulge of plasma membrane with nucleus & most of cytoplasm of Schwann cell just external to myelin sheath
o nodes of Ranvier: gaps in myelin sheath between adjacent Schwann cells
o white matter: myelinated fiber tracts in CNS
o gray matter: mostly nerve cell bodies & unmyelinated fibers in CNS
Action Potential:
- Conduction velocities of axons:
o Salutatory conduction: the presence of the myelin sheath insulates against leakage of charge & only allows generation of action potential at nodes of Ranvier between adjacent Schwann cells (or oligodendrocytes)
§ much faster than in unmyelinated axonsŠ the electrical signal jumps from node to node along the axon
Synapse: junction that mediates transfer of information from neuron to neuron or effector (muscle, gland)
- axodendritic & axosomatic most commonŠ also axoaxonic, dendrodendritic & dendrosomatic
- presynaptic neuron: conducts impulses toward synapse
- postsynaptic neuron: transmits signal away from the synapse
Neurotransmitters:
- acetyl choline (ACh) – released at neuromuscular junctions (excitatory for skeletal muscle; inhibitory for cardiac muscle)
- biogenic amines: catecholamines (dopamine, epinephrine & norepinephrine) & indolamines (histamine & serotonin)Š
- amino acids: GABA, glycine, aspartate, & glutamateŠ
- peptides: substance P, endorphins & enkephalinsŠ
Brain Regions:
- cerebral hemispheres
- diencephalons
- brain stem (midbrain, pons & medulla oblongata)
- cerebellum
Protective Coverings of the Brain: cranium & cranial meninges
- meninges: 3 connective tissue membranes just external to brain
o dura mater: outer layer
o arachnoid: middle layer; subarachnoid space contains large capillaries & CSF
o pia mater: innermost layer; just superior to cerebrum
- cerebrospinal fluid: formed by choroid plexuses hanging from the roof of the ventricles
Cerebral Hemispheres:
- superior part of brain; ~ 83% of total brain mass
- 3 regions: cerebral cortex (gray matter), white matter & basal nuclei
- gyri: elevated ridges of brain tissue, separated by shallow grooves called sulci
- fissures: deeper grooves separating larger regions of brain
o longitudinal fissure: separates cerebral hemispheres
o transverse fissure: separates cerebral hemispheres from cerebellum
- deep sulci divide cerebral hemisphere into 5 lobes: frontal, parietal, temporal, occipital & insula
o insula: cerebral lobe buried deep within lateral sulcus
Cerebral Cortex: conscious mind; awareness, communication, memory & understanding & initiation of voluntary movements
- Motor Areas:
o primary (somatic) motor cortex: pyramidal cells: large neurons allow precise control over voluntary skeletal muscle movement; form pyramidal (corticospinal) tracts
§ damage (from strokeŠ) paralyzes muscles on side of body opposite that of lesion (only voluntary movement lost)
o premotor cortex: controls learned repetitious or patterned motor skills (playing musical instrument, typing) & helps in planning movements
§ damage results in loss of learned skills, but movement of muscles is often still possible
o Broca¹s area: in one hemisphere only (generally left)
§ special motor speech area – controls muscles of tongue, throat & lips during (& possibly in planning of) speech
Lateralization: each hemisphere gas unique abilities
- cerebral dominance: one hemisphere dominant for language (usually left)
Basal Nuclei (basal ganglia): subcortical nuclei deep within cerebral white matter
- regulate motor control (muscle movements, & perhaps also attention & cognition)
- corpus striatum: composed of lentiform nucleus & caudate nucleus
o lentiform nucleus: composed of putamen & globus pallidus
- amygdala: on tail of caudate nucleus; part of limbic system
Diencephalon: central core of forebrain; surrounded by cerebral hemispheres
- thalamus:
o sorts & edits sensory information & relays to appropriate area of sensory cortex & association areas
- hypothalamus:
o connected to pituitary gland by stalk called infundibulum
o main visceral control center; controls homeostasis
- epithalamus:
o pineal gland: secretes hormone melatonin – helps in regulation of sleep-wake cycle
o choroid plexus: secretes CSF
Brain Stem:
- midbrain: between diencephalon & pons
o corpora quadrigemina: midbrain nuclei
§ superior colliculi: visual reflex centers
§ inferior colliculi: auditory relay
o substantia nigra: pigmented nucleus; contains melanin, a precursor of the neurotransmitter dopamine
o red nucleus: pigmented nucleus; rich blood supply & iron pigment; motor relay for limb flexion
- pons: between midbrain & medulla oblongata
o conduction tracts (pons = bridge); complete pathways between higher brain centers & spinal cord; relays between motor cortex & cerebellum
- medulla oblongata: most inferior part of brain stem; blends with spinal cord
o pyramids: large pyramidal tracts descending from motor cortex
§ tracts cross over to opposite side before entering spinal cordŠ cerebral hemispheres control voluntary movements of muscles on opposite side of body
§ sensory & visceral motor nuclei (control heart rate & blood vessel diameter, breathing rate, vomiting, coughingŠ)
Cerebellum: dorsal to pons & medulla; inferior to occipital lobes
- processes information from cerebral motor cortex & from sensory pathways and sends instructions to cerebral motor cortex & motor centers to regulate balance, posture & coordinated skeletal muscle movement
Functional Brain Systems:
Limbic System: regions of the medial aspects of each cerebral hemisphere & diencephalons encircling brain stem (limbus = ring) & linked by the fornix
- emotional brain
o amygdala: recognizes angry or fearful facial expressions, assesses danger & elicits fear response
o cingulate gyrus: regulation of expression of emotions & feelings of frustration
o hippocampus: plays a role in storing information in long-term memory
Reticular Formation: extends through core of brainstem
- reticular activating system: maintains cerebral cortical alertness
- filters out repetitive stimuli
- motor nuclei help regulate skeletal & visceral muscle activity
Memory:
- memory involves the storage & retrieval of information
- memory storage occurs in stages & is continually changing
- the hippocampus of the limbic system & surrounding structures play roles in memory processing
- Anterograde amnesia: ability to associate new information with old is lost; person lives in here & now, but can still learn skills
- Retrograde amnesia: loss of memories formed in the distant past
Internal Anatomy of Spinal Cord:
- grooves: anterior median fissure & posterior median sulcus
- butterfly-shaped gray matter surrounded by outer white matter
o anterior, posterior & lateral horns contain the cell bodies of somatic motor neurons, autonomic sensory neurons & autonomic motor neurons, respectively
o gray commissure: across center of gray matter; contains central canal – an open space continuous with the ventricles of the brain (arises from 4th ventricle)
- white matter: nerve fibers allow communication between different parts of spinal cord & between spinal cord & brain
o anterior, posterior & lateral columns (funiculi)
Sensory Receptors: specialized to respond to changes (stimuli) in environment
Classification by Stimulus Type:
- mechanoreceptors: respond to touch, pressure (including blood pressure), vibration, stretch & itch
- thermoreceptors: respond to temperature changes
- photoreceptors: respond to light energy
- chemoreceptors: respond to chemicals in solution (molecules smelled, tasted; changes in blood pH, solutes)
- nociceptors: respond to pain from potentially damaging stimulus
Classification by Location:
- exteroreceptors: sensitive to stimuli arising outside body (touch, pressure, pain receptors)
- interoreceptors: sensitive to stimuli arising outside body (internal viscera, blood vesselsŠ)
- proprioceptors: respond to internal stimuli in skeletal muscle, tendons, joints, ligaments & connective tissue surrounding muscles & bones
Nerves & Associated Ganglia:
Nerve: cordlike organ of PNS consisting of bundles of axons enclosed in layers of connective tissue
- each axon enclosed in endoneurium
- bundles of fibers (fascicles) enclosed in perineurium
- bundles of fascicles enclosed in epineurium
- sensory (afferent) nerves: carry impulses toward CNS
- motor (efferent) nerves: carry impulses away from CNS
- mixed nerves: contain both sensory & motor fibers (can be somatic &/or autonomic fibers)
- peripheral nerves classified as spinal nerves or cranial nerves
- ganglia: collections of neuron cell bodies associated with nerves in PNS
Cranial Nerves: know names, #¹s & basic functions
Spinal Nerves: 31 pairs
- 8 pairs of cervical
- 12 pairs of thoracic
- 5 pairs of thoracic
- 5 pairs of sacral
- 1 pair of coccygeal
Nerve Plexuses:
- cervical plexus: cranial nerves C1-C5; supplies skin & muscles of head, neck & superior part of shoulders & chest
- brachial plexus: cranial nerves C5-T1; supplies shoulders & upper limbs
- lumbosacral plexus: lower limb; branches to pelvis, abdomen & buttocks
o lumbar plexus: spinal nerves L1-L4; supplies anterior abdominal wall, external genitals & part of lower limbs
o sacral plexus: spinal nerves L4-S4; supplies buttocks, perineum & lower limbs
o coccygeal plexus: spinal nerves S4-Co; supplies small area of skin in coccygeal region
Reflexes:
- somatic reflexes: lead to contraction of skeletal muscles
- autonomic (visceral) reflexes: lead to responses from smooth muscle, cardiac muscle & glands
Autonomic Nervous System – system of motor neurons within the motor division of the peripheral nervous system that innervates smooth muscle, cardiac muscle & glands.
- also known as the involuntary nervous system (subconscious control) & the general visceral motor system
Parasympathetic division: ³resting & digesting² systemŠ low energy use (low blood pressure, heart rate & respiratory rate), active digestion of food & elimination of waste; pupils of eyes are constricted & lenses accommodated for close vision
Sympathetic division: ³fight or flight² systemŠ activated during emergency or threatening/stressful situations; rapid heart & breathing rate, greatly decreased gastrointestinal & urinary tract activity, pupils dilated. Visceral blood vessels are constricted & blood is shunted to active skeletal muscles
- Know basics of chart comparing the branches of the motor division of the PNS & the divisions of the autonomic nervous system (from study guide for exam 4)
Taste Buds & the Sense of Taste
- taste buds: about 10,000 in adult human; most on the tongue
· Most taste buds are located within papillae (projections of the tongue mucosa)
· 4 types of papillae:
o fungiform papillae: most numerous type; found scattered over the surface of the tongue, but most at the tip & along sides
o foliate papillae: along both sides of tongue towards posterior
o circumvallate (vallate) papillae: form an inverted V at the back of the tongue; 7-12 with ~250 taste buds each
o filiform papillae: in center of tongue; no taste buds
· each taste bud has 40-100 epithelial cells of 3 types:
o gustatory (taste) cells: receptor cells with membranes with gustatory hairs that sense stimuli; contacted by dendrites of sensory neurons; replaced every 7-10 days
o supporting cells: most cells within taste bud; insulate receptor cells
o basal cells: stem cells; divide & differentiate into supporting cells
· pure taste sensations are grouped into 4 types:
o sweet: sensed at anterior tip of tongue
o salty: sensed at anterior sides of tongue
o sour: sensed at middle sides of tongue
o bitter: sensed at posterior of tongue
· afferent fibers carrying taste information from the tongue:
o chorda tympani branch of the facial nerve (cranial nerve VII) transmits impulses from taste buds at the anterior 2/3 of tongue
o glossopharyngeal nerve (cranial nerve IX) transmits impulses from taste buds on the posterior 1/3 of tongue
o vagus nerve (cranial nerve X) transmits impulses from a few taste buds on the epiglottis & pharynx
· trigeminal nerve (cranial nerve V) does not innervate taste buds, bud transmits impulses from nociceptors that discriminate texture in foods, as well as hot/cold & spicy foods
- structure of the eyeball
· fibrous tunic: dense, avascular CT; 2 regions:
o sclera: white of eye
o cornea: anterior 1/6 of fibrous tunic; transparent CT
§ corneal epithelium: 2layersŠ stratified squamous epithelium on outside with deep simple squamous epithelial tissue
· vascular tunic (uvea): 3 regions:
o choroid: highly vascular dark brown membrane; blood vessels supply nutrients to all tunics
§ melanin from melanocytes absorb light & prevent scattering
o ciliary body: contains smooth muscle bundles (ciliary muscles) that control lens shape
o iris: lies between cornea & lens; has round central opening called pupil
§ pupil opens & closes to control light entry into eye; controlled by smooth muscle in iris
· sensory tunic (retina): consists of 2 layers:
o outer pigmented layer: a single cell layer thick; contains phagocytic pigmented epithelial cells that absorb light & prevent scattering
o inner neural layer: outpocketing of brain; 3 main types of neurons:
§ photoreceptors: rods & cones
· rods: respond to dim light; blurry shades of gray
· cones: respond to bright light; sharp, color vision
§ bipolar cells: link between photoreceptors & ganglion cells
§ ganglion cells: receive input from bipolar cells & their axons leave eye as optic nerve
o blind spot (optic disc): location on retina where the optic nerve exits eye
o fovea centralis: only cones present; region of greatest visual acuity
· photoreception:
o visual pigments of rods & cones are a combination of retinal (a vitamin A derivative) & opsins (pigmented proteins)
o rods use rhodopsin (deep purple pigment)
o cones use 3 different types of opsins to yield:
§ red cones
§ green cones
§ blue cones
o excitation of photoreceptors occurs following a chain of reactions initiated by the isomerization (structural change) of retinal & detachment of retinal from opsin (bleaching of the pigment) after being struck by light
o color blindness: a congenital lack of one or more cone types
The Ear: Hearing & Balance
- outer (external) ear: consists of the auricle (pinna) & the external auditory canal (travels from auricle to eardrum; ceruminous glands secrete earwax)
- tympanic membrane (eardrum): boundary between outer & middle ear
· vibrates with frequency of sound waves entering through external ear; transfers vibration to ossicles of middle ear
- middle ear (tympanic cavity): small air-filled cavity within temporal bone lined with mucosa & flanked by the eardrum & 2 openings (oval (vestibular) window & round (cochlear) window)
· the anterior wall of the middle ear contains an opening to the auditory tube (leads to nasopharynx)
· contains 3 ossicles (small bones) suspended by ligaments:
o malleus (hammer) – attaches to eardrum
o incus (anvil)
o stapes (stirrup) – attaches to oval window of vestibule
- inner ear (labyrinth): consists of bony labyrinth & membranous labyrinth
· bony labyrinth: cavity within the temporal bone filled with perilymph & containing the membranous labyrinth
· membranous labyrinth: floats in perilymph within bony labyrinth; filled with fluid called endolymph
· vestibule: central region composed of 2 sacs – the saccule & utricle
o contains equilibrium receptors for balance called maculae
· semicircular canals: 3 rounded tubes projecting from utricle through swellings called ampullae
o ampullae contain equilibrium receptors called crista ampullaris
· cochlea: snail-shaped chamber extending from the saccule
o contains cochlear duct housing the organ of Corti, which contains receptors for hearing
o 3 chambers (scala vestibuli, scala media & scala tympani)
Mechanisms of Equilibrium & Orientation:
- static equilibrium: maculae in the vestibule are sensory receptors for static equilibrium
· maculae respond to vertical & side-to-side head movements
- dynamic equilibrium: the crista ampullaris in the ampullae of the semicircular canals is the receptor for dynamic equilibrium