A&P exam 3

ch 21, 22, 23

tunica interna

innermost layer of blood vessel, closest to lumen and continuous w/ endocardium; simple squamous epithelium and basement membrane

tunica media

middle layer of blood vessel, smooth muscle and elastic fiber; function to regulate diameter

tunica externa

outermost layer adjacent to surrounding tissue, elastic and collagen fibers; function for protection

vasa vasorum

tiny vessels to the vessels

elasticity

elastic tissue in tunica interna and media, allow arteries to accept blood under great pressure and send to system

arteries

move blood away from heart

contractility

due to smooth muscle of tunica media, allows artery to change lumen size in response to injury

elastic arteries (conducting)

large diameter, thick tunica media dominated by elastic fibers, less smooth muscle; receive blood under pressure, propel onward; recoil and convert potential energy into kinetic energy

muscular arteries (distributing)

medium diameter, greater smooth muscle and fewer elastic; distribute blood with no recoil

anastomoses

union of branches of 2 or more arteries or veins that supply same region of body

collateral circulation

alternate route of blood flow

end arteries

do not form anastomosis

arterioles

small, almost microscopic arteries regulate blood flow to capillaries; \~400M, 15-300microm diameter

resistance

opposition to blood flow from arteries to capillaries, altering arterial blood pressure; arterioles regulate

metarteriole

terminal end of arteriole

metarteriole capillary junction

located at precapillary sphincter, monitors blood flow

capillary

microscopic vessels, connect arterioles and venules; \~20B, diameter

microcirculation

flow of blood through capillary

precapillary sphincter

rings of smooth muscle fibers regulate blood flow through true capillaries

thoroughfare channel

direct route from arteriole to ventless, passes by branching of capillaries

continuous capillary

continuous tube interrupted by intercellular clefts, found in CNS, lung, muscle, skin

fenestrated capillary

endothelial cell have fenestrations (pore) 70-100nm; found in kidney, SI, choroid plexus in brain, cilliary process of eyes, endocrine gland

sinusoid capillary

large fenestration, incomplete or absent basement membrane; found in liver, spleen, anterior pituatary, parathyroid, adrenal

venules

small vessels formed by union of several capillaries, porous for exchange of nutrient

veins

formed by union of several venules; thicker tunica externa than tunica interna; contain valves to prevent back flow

diffusion

action of capillary exchange for O2, CO2, glucose, amino acid, some hormones; sinusoid capillary allow protein and RBC to pass

trancytosis

endocytosis of mainly large lipid and insolvable molecules

Bulk Flow

passive process in which large # of ions, molecules, or particles in fluid move in same direction; move from low pressure to high pressure

hydrostatic pressure

pressure of water in blood plasma exerts against walls

osmotic pressure

pressure due to presence of proteins in blood

filtration

pressure driven movement of fluid and solute from blood capillary to interstitial fluid

reabsorption

pressure driven movement of fluid and solute from interstitial fluid into blood capillaries

Starling Law of Capillaries

volume of fluid and solutes reabsorbed is as large as volume filtered

net filtration pressure

balance of pressures in tissues between reabsorption and filtration

blood flow

volume of blood that flows through tissue in given time period

cardiac output

HR x stroke volume; mean arterial pressure / resistance

blood pressure

pressure exerted on walls of blood vessel, generated by ventricular contraction

systolic BP

highest BP during systole (contraction)

diastolic BP

lowest arterial pressure during diastole (relaxation)

mean arterial pressure

average BP in arteries, rough 1/3 between diastolic and systolic pressures

vascular resistance

opposition to blood flow due to friction between blood and vessels

systemic vascular resistance / total peripheral resistance

all resistance by system, most due to arteriole, capillary, and venules

venous return

volume of blood flowing back to heart, due to pressure generated by contraction of left ventricle and maintained by skeletal muscle, valves and pressure change

cardiovascular center

group of neurons in medulla oblongata that regulate HR, contractility, vessel diameter; input from senses and higher brain regions; output to cardio accelerator or vagus nerve

vasomotor tone

moderate state of tonic contraction sent by sympathetic division continuously sends to vessel smooth muscles via vasomotor nerves

baroceptors

pressure sensitive sensory receptors monitor stretch of walls of vessels and atria

carotid sinus reflex

concerned with maintaining BP in brain, initiated by barocepters in carotid sinus, impulse propagates over sensory axon in cranial nerve IX

aortic reflex

concerned with systemic BP and initiated by baroceptors in aorta or attached to aortic arch by vagus nerve

chemoreceptors

sensitive to chemicals, located close to baroceptors in carotid sinus and aorta, monitor levels of O2, CO2, and H

auto regulation of BP

ability of tissue to automatically adjust blood low to match metabolic demand

myotonic response

contracts forcefully when stretched, relaxes when less stretched

vasodilation

caused by K, H, lactic acid, adenosine, NO, trauma and inflammation which releases kinins and histamines

vasoconstriction

caused by TXA2, superoxide radicals, serotonin

pulse

expansion and elastic recoil of artery wall creating traveling pressure wave with heart beat

Korotkoff sounds

sounds heard when taking BP

shock

inadequate blood flow resulting in failure of CV system to meet metabolic demand

hypovolemic shock

due to decreased blood volume

cardiogenic shock

due to poor heart function

vascular shock

due to inappropriate vasodilation

anaphylactic shock

release of histamine and drop of BP

obstructive shock

due to obstruction of blood flow

immunity/ resistance

ability to ward off pathogens

susceptibility

lack of resistance to pathogens

Nonspecific / Innate Immunity

present at birth and includes general defense

Adaptive Immunity

activation of specific lymphocytes that combat specific pathogens

lymphatic system

system that carries out immune response, including lymph, lymph vessels, spleen; drain interstitial fluid, transport dietary fat

lymph capillaries

closed at one end, located between cells, merge to vessels; located throughout except avascular tissue, CNS, spleen and red bone marrow; overlapping endothelial cells work as one way valves for fluid to enter

anchoring filaments

attach endothelial cells to surrounding tissue

lacteal

lymph capillary in villus of SI which transports digestive fat into blood

chyle

lymph in lacteal of SI which appears creamy white

lymph vessel

merging of capillaries which have thin walls and many valves

lymph trunk

drains from lower limbs, wall and viscera of pelvis, kidneys, adrenal glands, and abdominal wall; lymph passes from vessels to node to trunk

intestinal trunk

drains lymph from stomach, intestines, pancreas, spleen, liver

bronchomediastinal trunks

drain lymph from thoracic wall, lung, and heart

subclavian trunks

drain upper limbs

jugular trunks

drain head and neck

lymph ducts

merge of lymph trunks into 2 main channels

thoracic duct (left lymphatic duct)

dilation (cisterna chyli) in beginning and is main collecting duct of lymph system, drains all lower and left side body into junction of left internal jugular and left subclavian

right lymphatic duct

receives lymph from right upper body and drains into junction of right internal jugular and right subclavian vein

respiratory pump

factor of lymph flow; flow due to pressure change that occurs by inhalation, pressure lower in thorax, valves prevent back flow

efferent lymph vessels

carry lymph from lymph nodes

afferent lymph vessels

carry lymph from lymph capillaries to lymph nodes

primary lymph organs

where immune cells become immunocompetent, capable of mounting immune response

red bone marrow

formation of immunocompetent B cells and pre-T cells

thymus

pre-T cells migrate here to become immunocompetent

secondary lymph organs

lymph nodes, spleen, and lymphatic nodules, site of most immune response

lymphatic nodules

not considered organ bc lacks a capsule; spleen and nodes surrounded by C.T. capsule

trabecule penetrate

extensions of CT capsule that divide lobes of thymus into lobules

outer cortex of thymus

large T cells, scattered dendritic cells, epithelial cells and macrophages

pre T cells

move from red bone marrow to cortex to mature

dendritic cells

derived from monocytes, assist in T cell maturation

epithelial cells

help “educate” pre T cells

thymus macrophages

clear out debris of dead cells, particularly pre T cells; only 2% of pre T cells survive and enter medulla

central medulla of thymus

widely scattered mature T cells, scattered dendritic cells, epithelial cells, and macrophages

thymus corpuscles

epithelial cells arranged in concentric layers of flat cells, cells degenerate and become filled w/ keratohyalin granules and keratin; may be site of T cell death

lymph nodes

encapsulated oval structures located along lymph vessels (\~600), covered by dense CT capsule

trabeculae

capsular extension

stroma

supporting framework of CT in lymph node, composed of capsule, trabeculae, reticular fiber and fibroblast

lymphatic nodules (follicles)

egg shaped aggregates of B cells w/in outer cortex

primary lymphatic nodules

consist chiefly of B cells