Foundations Exam 1 Week 1

Front 1

Functions of Epithelia

Back 1

1. Forms a barrier (all epithelia)
2. Resists abrasion (vagina, anal canal, etc.)
3. secretion (pancreas)
4. absorption and excretion (kidney)
5. passive exchange

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Endothelium

Back 2

lines all blood vessels and the heart

Front 3

Mesothelium

Back 3

lines the pleural, pericardial, and abdominopelvic cavities

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simple squamous epithelia

Back 4

allows for passive exchange, single layer

lining of alveoli, endothelium (blood vessel lining), mesothelium (body cavity lining), some kidney tubules

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simple cuboidal epithelia

Back 5

lining of kidney tubules, many ducts of salivary glands and pancreas

excretion and absorption

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simple columnar epithelia

Back 6

lining of GI tract, bronchioles in lung, oviduct, uterus in female reproductive tract

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pseudostratified epithelium

Back 7

all cells touch basal lamina but not all reach the surface

bottom cells will differentiate into the taller cells

respiratory epithelium, much of male reproductive tract

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stratified squamous epithelia

Back 8

resists abrasion, barrier between body and outside world

epidermis of skin (keratinized), lining of oral cavity, esophagus, anal canal,vagina, cervix, distal urethra (non-keratinized)

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stratified cuboidal epithelia

Back 9

lining of sweat gland ducts

Front 10

stratified columnar

Back 10

lining of some salivary gland ducts

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stratified columnar epithelia

Back 11

lining of some salivary gland ducts

Front 12

transitional epithelium

Back 12

urothelium

lining of much of the urinary tract, including urinary bladder

occurs only in the urinary system

capable of extensive stretching due to umbrella (dome) cells at luminal surface

ability to expand and shrink with urine volume

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basal surface specializations

Back 13

- faces connective tissue and blood supply
- sits on basal lamina
- adheren junctions and hemidesmosomes contribute to attachment

Front 14

adherens junctions

Back 14

- basal surface
- attached to actin filament
- mechanical
- always associated with tight junctions

Front 15

hemidesmosomes

Back 15

- basal surface
- attach cell to substrate
- intermediate filaments

Front 16

lateral surface specializations

Back 16

- face adjacent cells
- presence of tight junctions (zonula occludens), adheren junctions (zonula adherens), desmosomes

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tight junction

Back 17

- zonula occludens
- band around cell, between cells to seal
- always associated with adheren junctions
- nonmechanical

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desmosomes

Back 18

- macula adherens
- intercellular attachment plaques that link to intermediate filaments in cytoskeleton

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apical surface specializations

Back 19

- faces the outside world
- contains microvilli (brush border), cilia

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microvilli

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- fingerlike projections of plasma membrane supported by a core of actin filaments
- function: increase surface area and absorption

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brush border

Back 21

dense, orderly array of microvilli

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cilia

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motlie surface projections with a core of microtubule "doublets" arranges in 9+2 array called axoneme

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dynein

Back 23

protein that cause microtubules to move ( in the presence of ATP)

Front 24

basal lamina

Back 24

- thin layer at bottom of epithelial cells
- secreted by epithelial cells
- not produced by connective tissue

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characteristics of epithelia

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- high cell density
- avascular
- glands in the body are formed from epithelium

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characteristics of connective tissue

Back 26

- abundance of extracellular molecules
- low density of cells

Front 27

functions of connective tissue proper

Back 27

1. mechanical support
2. metabolic support
3. defense
*major site of initiation of inflammation

Front 28

why is connective tissue a major site of inflammation initiation?

Back 28

- carries majority of vasculature
- inflammation is primarily a vascular process
- white blood cells have their effect primarily in connective tissue

Front 29

extracellular matrix

Back 29

- composed of various kinds of fibers and ground substance
- fibers and ground substance of ECM are secreted by fibroblasts

Front 30

ground substance

Back 30

non-fibrous molecules and the fluid bound to them

Front 31

Type I collagen

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- most abundant in body
- forms bundles that provide mechanical reinforcement to CT
- basophilic
- longitudinal
- synthesized from fibroblasts

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Type III collagen

Back 32

- reticular fibers
- subset of fibroblasts called mesenchymal reticular cells
- form networks rather than bundles
- forms scaffolding in some organs (main support)
-liver, spleen, lymph nodes
- some support of: lamina propria and blood vessels

Front 33

Elastic fibers

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- provide recoil ability to CT
- elastin associates with fibrillin
- present in large blood vessels
- forms fibers and sheets
-Marfan's syndrome

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ground substance

Back 34

gel-like matrix composed of mainly proteoglycans and hyaluronan

Front 35

proteoglycans

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- synthesized in the RER
- core protein + sugar
- unbranched
- long
- side chains
- glycosaminoglycan (GAG)

Front 36

glycosaminoglycans (GAG)

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- highly negatively charged
- attracts cations which in turn attracts water
- forms a hydrated gel
- fills volume
- resists compression
- substrate for cell travel

Front 37

glycoproteins

Back 37

- synthesized in the RER
- core protein + sugar
- branched
- short side chains
- side chains are oligosaccharides

Front 38

dermatan sulphate proteoglycan

Back 38

proteoglycan present in the skin

Front 39

aggrecan

Back 39

proteoglycan present in cartilage and in developing heart and brain

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heparan sulphate proteoglycan

Back 40

proteoglycan present in basal lamina

Front 41

hyaluronan

Back 41

hyaluronic acid
- unique GAG
- not synthesized in the RER ( on plasma membrane of fibroblasts)
- not linked to a core protein
- immense in size
- composed of up to 25,000 repeating disaccharide units
- negative charge
- forms hydrated gel-like substance
- present in cavities of joints (lubricant) and vitreous of the eye (allows light transmission)

Front 42

fibronectins

Back 42

adhesive glycoproteins that attach cells to collagens

Front 43

integrins

Back 43

transmembrane proteins that mediate attachment of cells to extracellular matrix

- essential for migration of macrophages and other immune cells, and of many types of cells during embryogenesis

Front 44

laminin

Back 44

adhesive glycoprotein which binds integrins in basal membranes of epithelial cells to collagen

Front 45

Type IV collagen

Back 45

- forms a mesh
- only found in basal lamina
- binds laminin to other components of basal lamina and underlying ECM
- essential for integrity of basal lamina

Front 46

primitive mesenchymal cells

Back 46

origin: embryonic mesenchyme

characteristics: near small blood vessels
functions: CT stem cells

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fibroblasts

Back 47

Origin: primitive mesenchymal cells

functions: -synthesize collagen fibers, elastic fibers, proteoglycans, glycosaminoglycans
-wound healing
- fibrosis (scarring)
- differentiate into myofibroblast during wound healing
- secrets ECM

Front 48

adipocytes

Back 48

origin: primitive mesenchymal cells

characteristics: large cells, large lipid droplets, nucleus and organelles found in the periphery

function: store and mobilize lipids, 'chicken wire' network

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mast cells

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origin: stem cells in bone marrow

characteristics: near small blood vessels, contain secretory granules

functions: - degranulate (histamine) in response to injury, toxins, allergens
- initiation of inflammatory response
- mediator of allergic reaction

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anaphylaxis

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a systemic allergic reaction which can cause death in minutes due to bronchoconstriction and severe drop in blood pressure

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plasma cells

Back 51

origin: antigen-stimulated B cells

characteristics: found in CT, near activation site, lots of RER

functions: secrete antibody, occurs during chronic inflammation

Front 52

post-capillary venules

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- leakiest part of the blood vascular system ( even more leaky than capillaries)
- site where white blood cells exit the blood and into tissue

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coenzymes

Back 53

special reactant for enzyme, essential for activity,derived from vitamins, may attach and detach from enzyme

Front 54

prosthetic groups

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organic, covalently attached to enzyme

Front 55

isozymes

Back 55

- two different enzymes that catalyze same reaction
- may utilize the same substrate

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nonfunctional plasma enzymes

Back 56

- appear in blood but have no physiological function in blood
- if found in blood, then indicative of cellular damage
example: AST/ALT/glutamyl transferase in blood means liver damage
- if mitochondrial enzymes are found in blood, indicative of severe cell injury and death

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allosteric regulation

Back 57

- effector molecule binds to enzyme at a site different from substrate
- changes conformation
- affects ability of enzyme to bind to substrate
example: hemoglobin

Front 58

enzyme regulation

Back 58

- substrate concentration
- cofactors
- isozymes
- allosteric regulation

Front 59

Kcat

Back 59

catalytic constant
- the efficiency of an enzyme to catalyze a reaction

Front 60

Km

Back 60

michaelis constant
- concentration of substrate required for 1/2 of the enzymes to be substrate bound and 1/2 Vmax
- an enzyme could have different Km's for different substrates

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collagen

Back 61

- most abundant structural protein in the body
- made in fibroblast (chondrocytes)
- alpha chain form into a tight triple helix

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triple helix

Back 62

- three pro-collagen (alpha) chains wound together
- 3.0 residues per turn
- rich in proline (smallest amino acid)
- glycine at every 3rd position
[Gly - X - Y]
- X is usually proline
- Y is usually lysine
- disulfide bonds: cross links between cysteines

Front 63

Collagen Type I

Back 63

- most abundant collagen in the body; present in scar tissue
- found in skin, tendon, arterial walls, bone (fibroblasts)

Front 64

Collagen Type II

Back 64

- hyaline cartilage, 50% of all cartilage protein
- cartilage, vitreous humor (chondrocytes)

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Collagen Type III

Back 65

- collagen of granulation tissue; produced quickly by young fibroblasts before tougher type I collagen is synthesized
- skin, muscle, frequently found with type I collagen (quiescent hepatocytes epithelial; fibroblasts)

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Collagen Type IV

Back 66

- part of filtration system in capillaries and glomeruli of kidney nephron
- all basal lamina (epithelial cells, endothelial cells, regenerating hepatocytes)

Front 67

osteogenesis imperfect (OI)

Back 67

"brittle bone disease"
- mutations primarily in the COL 1A1 and COL 1A2 genes
- encode the pro-alpha-1(I) and pro-alpha-2(I) chains
-affects type I collagen
-skin, tendons, arterial walls, bones
-protein is misfolded, then degraded
- significantly decreases the amount of collagen
- hyperelasticity of skin
- lack of strength and stiffness
- hearing loss, bone defects, muscle weakness, short stature, immobility

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Scurvy

Back 68

- vitamin C deficiency
- reduces hydroxylation of proline and lysine
- abnormal collagen trimer formation and cross-linking are abnormal
- weakened blood vessels and bleeding gums

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Ehlers-Danlos Syndrome (EDS) Type V

Back 69

- deficiency of lysyl oxidase
- inability to form stable crosslinks
- sx: thin skin and cardiac valves, hernias

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EDS Type VI

Back 70

- deficiency of lysyl hydroxyls
- lack of OH-Lys formation
- diminished cross-linking and immature fibers
- sx: hyperextensible joints, eye defects

Front 71

EDS Type VIIB

Back 71

- cleavage of N-terminal extensions is incomplete
- hip dislocations

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collagen turnover

Back 72

- dramatic degradation and re-synthesis of collagen fibrils during embryonic development
- in adults, half-lives of many weeks or months
- in bone, continually degraded and resynthesized as remodeling occurs
- example: high collagen turnover may be a sign of cancer

Front 73

degradation of collagen

Back 73

- initiated by cleavage of molecule at specific sites by collagenases
- after collagen unfolds, further degraded by gelatinizes and stromelysin
- increase in excretion in urine of hydroxyproline and hydroxylysine

Front 74

advanced glycosylation end products (AGE)

Back 74

- non-enzymatic glycosylation of collagen --> reversible short term
- AGE forms in long term high levels of sugar --> irreversible
- cross linking of lysine is permanent
- long half life allows for many cross links to occur
- prevents collagen turnover
**complications of diabetes
- cardiovascular disease
due to stiffer collagen --> stiffer vessels

Front 75

Smooth muscle features and locations

Back 75

- relatively weak, slow contractions, involuntary control
- contains few blood vessels, bordered by CT
- found in the walls of hollow organs -- gastrointestinal tract, portions of the reproductive and urinary tracts, walls of blood vessels, respiratory passages
- can regulate peristalsis in gut, blood pressure and air flow in blood vessels and bronchi

Front 76

Smooth muscle fibers

Back 76

- elongated cells,spindle-shaped
- single nucleus, located near center of cell
- profiles vary in diameter
- "cork screw" nuclei
- no special cells with stem-like properties
- "dense bodies" where actin filaments in smc's attach to each other and to plasma membrane

Front 77

skeletal muscle features

Back 77

- rapid, powerful contractions under voluntary control
- dense, collagenous sheath of CT
- blood vessels and nerves run in CT, penetrate outer sheath

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skeletal muscle fibers

Back 78

- size: large, ~uniform <10x RBC
- staining: eosinophilic
- Nuclei: multiple, peripheral
- long, straight, unbranched, striated
- form muscle fascicles
- satellite cells have stem-cell properties

Front 79

cardiac muscle features

Back 79

- regular, powerful contractions, not under voluntary control
- found only in the heart and the portion of the pulmonary veins where they join the heart
- lots of blood vessels and CT
- very few satellite cells or stem cells -->does not regenerate to any significant extent

Front 80

Cardiac muscle fibers

Back 80

- long, organized into fascicles, striated and contain sarcomeres
- stain eosinophilic
- branched
- 1 or 2 nuclei near center of cell
- intercalated discs

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Function of intercalated discs

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1. anchor sarcomeres
2. intercellular adhesion
3. allow rapid communication of electrical and chemical signals between muscle fibers

Front 82

Structural components of intercalated discs

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1. fascia adherens - anchors sarcomeres and contributes to cell-cell adhesion
2. desmosomes - contribute to cell-cell adhesion
3. gap junctions - rapid communication between cells

Front 83

parasympathetic ganglia

Back 83

contents: neuron cell bodies, unmyelinated neuronal processes, and schwann cells
- branch into submucosal plexus
- large nuclei belong to neuron
- small nuclei belong to schwann cells

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peripheral nerves

Back 84

- contain myelinated axons, unmyelinated axons or mixture of two
- sympathetic nerves is ganglia
- parasympathetic nerves in hollow organs
- nuclei belong to schwann cells
- three layers: epineurium, perineum, endoneurium

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myelin

Back 85

- multiple layers of wrapping around axons
- schwann cell wraps around portion of axon
- multiple nuclei seen on histology
- nodes of ranvier are unique to neural tissue
- increases conduction velocity

Front 86

structure of pancreas

Back 86

- exocrine portion of pancreas
- pancreatic acinar cells --> synthesize and secrete a variety of digestive enzymes precursors
- stroma: CT septa carrying nerves, blood vessels, etc.
- parenchyma: pancreatic acini + duct
- islets of langerhans: cluster of cells, endocrine portion of pancreas --> produce insulin and glucagon

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structure of liver

Back 87

- cylindrical lobules: interconnected epithelial plates one or two cells thick arranged in spokes around central vein
- hepatocytes: epithelial cells
- sinusoids: extensive network of large capillaries
- contains hepatic portal vein, hepatic artery
- bile canaliculi

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hepatic portal vein

Back 88

- connects two capillary beds
- carries blood from one organ to another
- drains capillaries in stomach, intestines, pancreas, spleen
- carries oxygen depleted blood

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bile canaliculi

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network of tiny tubules which drain into a system of bile ducts that drain into the gall bladder and duodenum

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hepatocytes

Back 90

- secrete bile (to duodenum)
- synthesize plasma proteins albumin, clotting factors
- process sugars, amino acids
- detoxify blood

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function of liver

Back 91

- excretion of bilirubin
- protein synthesis
- glucose homeostasis
- amino acid metabolism
- metabolism of drugs and toxins

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structure of kidney

Back 92

4 main elements:
- glomeruli
- tubules
- interstitium (connective tissue)
- vessels

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Tunica intima

Back 93

- endothelium
- basal lamina
- thin CT (barely visible in healthy tissue)
- internal elastic lamina (medium and large arteries)

Front 94

tunica media

Back 94

- collagen (very fine, not visible)
- smooth muscle
- dispersed elastic sheets called elastic lamallae
- visible external elastic lamina (large arteries)

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tunica adventitia

Back 95

- loose CT
- collagen
- reticular fibers
- small blood vessels and peripheral nerves

Front 96

vaso vasorum

Back 96

- bring nutrients, O2, blood to tunica media
- located in tunica adventitia

Front 97

aorta

Back 97

- an elastic artery
- tunica media: thick (~ 40 layers)
--> contains many elastic lamellae
- need good amount of CT to withstand high velocity and pressure
- elastic lamellae absorbs energy during systole, delivers it back during diastole

Front 98

large arteries

Back 98

- tunica media contains fenestrated elastic sheets interspersed with smc's
- elastic lamellae store potential energy
- examples: aorta, pulmonary trunk

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medium (muscular) arteries

Back 99

- tunica media contains several layers of smc's
- visible internal elastic lamina
- example: femoral, brachial, ulnar, and renal arteries

Front 100

arterioles

Back 100

- tunica media contains few layers of smooth muscle
- non visible internal elastic lamina
- smallest arterioles deliver blood to the capillary bed
- adventitia blends with surrounding CT

Front 101

capillaries

Back 101

- very thin walled tubes composed of endothelium and underlying basal lamina
- exchange of nutrients, waste products, and gases between blood and tissues

Front 102

continuous capillary

Back 102

- no fenestrae
- tight junctions
- exchange across endothelium via transcytosis
- locations: CNS, lungs, muscles, and CT

Front 103

fenestrated capillary

Back 103

- fenestrae allow faster exchange
- examples: choroid plexus of brain, gall bladder, intestines, and endocrine glands

Front 104

sinusoidal capillary (sinusoid)

Back 104

- lumen is very large in diameter which slows blood flow
- large fenestrae allow blood plasma unimpeded access to tissue

Front 105

venules

Back 105

- large diameter endothelial tubes with little smooth muscle
- post capillary venules --> primary location for white blood cells to leave blood and enter tissues

Front 106

medium veins

Back 106

- tunica media contains smooth muscle
- tunica media is thinner than adventitia

Front 107

large veins

Back 107

- tunica media has more smooth muscle than a medium vein but less than a comparable artery

Front 108

tunica intima under healthy conditions

Back 108

endothelial cells:
- no clot formation or sticking of blood cells to walls
- tight juntions --> minimize cell and fluid loss
- transport select materials

Front 109

tunica intima in times of injury or disease

Back 109

- promote clots
- loose junctions allow movement from blood to tissue
- leukocyte attachment for exit into tissue
- lipid and smooth muscle cell accumulation to close up vessel

Front 110

pericytes

Back 110

- wrap around outside of blood vessel
- small arterioles, capillaries, and venues
- sphincters that contract to regulate blood flow in capillaries

Front 111

functions of pericytes

Back 111

1. wound healing and vessel growth
- stem cells that differentiate into smooth muscle
2. similar to smooth muscle cells
-pre capillary arteries regulate blood flow to capillary beds

Front 112

function of lymphatic vessels

Back 112

1. collect extracellular fluid and white blood cells from CT spaces
2. filter through lymph nodes
3. return to blood

Front 113

structure of lymphatic vessels

Back 113

- similar to veins
- thinner walls (low pressure)
- very permeable
- no tight junctions
- contain valves
- blind-ended tubes
- discontinuous basal lamina

Front 114

defects in lymphatic vessels

Back 114

failure of lymphatic vessels result in accumulation of fluid in tissues --> edema

Front 115

arteriovenous anastomoses

Back 115

shunt pathways that can regulate the flow of blood into capillary beds

Front 116

purpose of hydroxylation of proline

Back 116

- important role: aligning (assembling) the individual monomers in the proper register (alignment) of a tight helix required to form a triple helix

Front 117

defect in hydroxylation of proline

Back 117

if OH-Pro is not formed, the monomers fail to assemble into mature trimers and unprocessed collagens accumulate in the RER

Front 118

purpose of hydroxylation of lysine

Back 118

- essential for the subsequent glycosylation of the molecule by enzymatic attachment of sugars
- amount of OH-Lys and sugar content is determined by length of time in RER lumen

Front 119

consequences of increased glycosylation

Back 119

- hydroxyl groups on the sugars become hydrated
- lose its tensile strength
- babies have less tensile strength (more flexible) than adults due to more time spent in RER and more glycosylation

Front 120

purpose of glycosylation

Back 120

- aid in secretion to extracellular matrix and organization of fibrils

Front 121

consequences of defect in OH-Lys

Back 121

- diminished substrate for lysyl oxidase
-cross-link formation is markedly diminished
- collagen fibers fail to mature properly