circulatory system

Question 1

blood vessel structure

Answer 1

tunic intima- outer membrane basement
tunic media- vasoconstriction/ dilation, elastin
tunic externa-tough connective tissue, collagen fibres

Question 2

elastic arteries

Answer 2

thick walls
near the heart
elastin present in all tunics
conducting vessels- conduct blood away from the heart

Question 3

muscular arteries

Answer 3

thick tunica media

distributing vessels- change diameter to control blood flow to body regions and organs

Question 4

arterioles

Answer 4

smallest arteries
tunica media
resistance vessel-change diameter to control resistance to blood flow, controls flow into capillary beds within specific tissues/ organs

Question 5

capillaries

Answer 5

thin walls of tunic intimate and supportive basement membrane
change vessel- exchange nutrients, waste, gases, hormones with interstitial fluid & thus with cells

Question 6

continuous capillaries

Answer 6

endothelial cells joined by tight junctions to form smooth, lining
intercellular clefts- some gaps between endothelial cells allow limited passage of fluids and small solutes
pinocytitic vesicles ferry fluids and larger solutes across the capillary wall

Question 7

fenestrated capillaries

Answer 7

endothelial cells contain pores
pores increase permeability to rapid exchange of fluid and small solutes
found in areas of active filtration, absorption, or in endocrine glands

Question 8

sinusoidal capillaires

Answer 8

most leaky
large spaces between endothelial cells and large fenestrations, incomplete basement membrane
slow blood flow allows large molecules and cells to pass between the blood and tissues
found in the liver, lymphoid organs, adrenal medulla

Question 9

venues and veins

Answer 9

capillaries unite to form venues
venues unite to form veins  
tunica intima folds to form valves 
little smooth muscle or elsatin
thick tunic external of collagen fibres 
capacitance vessels- thick tunica external provides support for accommodating a large blood volume

Question 10

functions of veins and venues

Answer 10

veins= return blood to the heart, large capacity to hold blood and act as a blood reserve 
venules= drain bed capillary beds

Question 11

blood flow

Answer 11

volume of blood flowing through a vessel, organ or entire circulation in a given period
- is determined by blood pressure and resistance

Question 12

blood pressure

Answer 12

force exerted on a vessel wall by the blood in that vessel
force, generated by the pumping action of the heart that keeps blood moving, blood moves form an area of high pressure to lower pressure

Question 13

resistance

Answer 13

amount of friction blood encounters as it flow through a vessel

Question 14

3 primary TPR

Answer 14

blood viscosity
total blood vessel length
blood vessel diameter

Question 15

TPR viscosity

Answer 15

thickness or stickiness of a fluid
due to concentration of blood cells and plasma proteins
-> haematocrit =-> viscosity
plasma volume =-> viscosity

Question 16

TPR vessel length

Answer 16

resistance to flow increase as vessel length increases

changes overtime in children growth

Question 17

TPR vessel diametre

Answer 17

amount of contact between 2 surfaces determines the amount of friction=ease of movement
more contact the blood vessel has with the walls of the vessel means more friction between the blood and the vessel wall= more resistance to flow
-> diametre =

Question 18

flow, pressure and resistance

Answer 18

F= P/R
direct relo between f & P if P increase F increase
indirect repo between F & R if R increase F decreases
cardio vascular system maintains adequate blood flow by altering TPR

Question 19

during exercise blood flow to skeletal muscle must increase

Answer 19

vasodilation blood flow

pressure must -> by -> CO

Question 20

arterial blood pressure factors

Answer 20

elastic arteries can be stretched

volume of blood forced into elastic arteries by ventricular contraction

Question 21

systolic pressure

Answer 21

peak pressure generated in the large arteries when ventricle contract

Question 22

diastolic pressure

Answer 22

pressure in the large arteries during ventricular relaxation

Question 23

pulse presssure

Answer 23

PP= SP- DP

Question 24

mean arterial pressure

Answer 24

MAP= pressure that propels blood through the vessel
MAP decline with increasing distance from the heart
MAP= DP+(1/3 x PP)

Question 25

MAP

Answer 25

cab be calculated if blood flow F=P/R or F= MAP/R
and total blood flow is CO, CO=MAP/R
MAP=CO x R
-> Co/R will -> BP
as -> R via vasoconstriction there is less room in vessel for the blood, thus blood pushes harder abasing the vessel walls, -> BP
vasoconstriction will -> venous return -> CO,-> MAP

Question 26

alteration in BP

Answer 26

hypotension systolic pressure below 90
hypertension transient elevation due to exercise, illness, emotions
sustained systolic pressure over 140mmHg

Question 27

capillary blood pressure

Answer 27

ranges from 35 at arterial end to 15 at venous end of capillary bed
low capillary pressure is required because high pressure would damage his walled, fragile capillaries and most capillaries are very permeable so low pressure is adequate for fluid exchange with tissues

Question 28

venous return

Answer 28

1. valves compartmentalise blood to shift it in small volumes and prevent blood back flow
2. muscular pump skeletal muscle contraction squeezed veins and helps push blood toward the heart
3. respiratory pump- pressure changes during breathing help blood move toward the heart by squeezing abdominal veins as thoracic veins expand
4. pulsating of nearby arteries
5. venoconstriction of tunic media under symp control

Question 29

factors of blood pressure

Answer 29

CO (rapid, short term regulation)
peripheral resistance (rapid, short term regulation)
blood volume (slower, long term regulation)

Question 30

determine BP: CO

Answer 30

rapid, short term regulation of BP and blood flow
CO= SV x HR
-> SV/ HR=->CO=->BP

Question 31

determine BP: R

Answer 31

TPR rapid, short term regulation of BP and blood flow

vasoconstriction: ->R, BP
vasodilation: flow=

Question 32

determine BP: BV

Answer 32

slower, long term regulation of BP
controlled by renal and endocrine mechanism
-> BV, more blood pushing on blood vessel walls=

Question 33

regulation of blood pressure

Answer 33

autoregulation- occurs within tissue and is dependent on local conditions
neural regulation- cardiovascular centres, the autonomic nervous system and the baroreceptor reflex
renal mechanism
endocrine regulation

Question 34

autoregulation

Answer 34

tissue regulate their own BP and F in response to local conditions by altering arteriole diameter to regulate blood flow into capillary bed
intrinsic regulation
metabolic control ⬆️ co2, ⬇️ o2, ⬇️ pH arteriole dilation ⬆️ blood flow into capillary bed, restores homeostasis
myogenic (muscle) control
high systemic bp arteriole stretch, reflex constriction, ⬇️ blood flow into capillary bed= prevent damage

Question 35

neural regulation

Answer 35

1.cardioinhibitory
-para input into SA & AV nodes= slows HR=⬇️ CO
2.cardioacceletory
-symph input into SA &AV nodes, ⬆️ HR=⬆️ CO
input into centricualr myocardium, ⬆️ force of contraction, ⬆️ SV= ⬆️ CO
3. vasomotor
-symph vasomotor fibres to the smooth muscle of arterioles, changes in vasomotor tone, changes in vessel diameter- for peripheral blood vessels
input from the hypothalamus regulates blood flow to maintain body temp and cardiovascular function in symph

Question 36

baroreceptor reflexes

Answer 36

fucntion rapidly to protect against changes in blood pressure
carotid baroreceptor sinus relfex, monitors BP to ensure adequate blood flow to the brain
aortic baroreceptor reflex, monitors BP to maintain blood flow in the systemic circuit

Question 37

renal mechanism

Answer 37

1. direct mechanism
   BP directly determines rate of urine formation, alters BV, alters BP
   ⬆️ BP➡️ activates baroreceptor reflex➡️peripheral vasodilation➡️ ⬆️ renal blood flow ➡️⬆️ fileration rate in kidneys➡️⬆️ urine production➡️ ⬇️urine production ➡️⬇️ BV and thus BP

Question 38

indirect mechanism: hormones

Answer 38

renin angiotensin-aldosterone system (RAAS)
⬇️ BP, angiotensin II production which stimulates peripheral vasoconstriction➡️ ⬆️ R➡️ ⬆️ BP (⬆️ VR and thus CO)
stimulates aldosterone secretion➡️ ⬆️ renal reabsorption of Na ions and thus water from the filtrate➡️ below ⬇️ urine production ➡️ maintains BV and BP
stimulates ADH release ➡️ ⬆️ renal water reabsorption from the filterate ➡️ maintains BV snd BP [vasocontriction]
stimulates thrist➡️ ⬆️ BV & BP

Question 39

endocrine regulation

Answer 39

hormones that ⬆️ BP:
adrenalin & noradrenalin ➡️ rapid ⬆️ CO (⬆️ SV & HR) & peripheral vasoconstriction
angiotensin II ➡️ vasoconstriction, thirst & promotes secretion of aldosterone➡️ ⬆️ renal Na ion and water reabsorption
ADH➡️ peripheral vasoconstriction and ⬆️ renal water absorption

Question 40

hormones that ⬇️ BP

Answer 40

ANP:
produced by the heart in response to high BP
opposes the action of angiotensin II➡️ ⬇️ BV & BP

Question 41

capillary dynamics

Answer 41

blood flow through capillaries is slow and intermittent controlled by arteriole diameter in response to local condition
capillary exchange include:
1.exchange of solutes- respiratory gases, nutrients and waste
2.bulk flow of fluid

Question 42

capillary excahnge

Answer 42

1. diffusion through endothelial membranes
2. movemnt through intercellular clefts
3. movement through fenestration
4. active transport via vesicles: endocytosis and exocytosis

Question 43

bulk flow of fluid

Answer 43

fluid moves across capillary walls by bulk flow
out of capillary at the arterial end
into the capillary at the venous end
fluid moves through:
intercellular clefts, fenestration, sinusoids
bulk fluid flow determines the relative fluid volumed of the blood & ISF
direction and voumes of fluid movement is determined by opposing forces: hydrostatic and colloid osmotic pressures

Question 44

hydrostatic pressure

Answer 44

force exerted by fluid pushing against a tissue wall
capillary hydrostatic pressure
forces of the blood plasma on the capillary walls= blood pressure
pushes fluid and solutes out of capillaries through intercellular clefts/ fenestrations/ sinusoids at the arterial end of bed
some fluid cells and most proteins remain in the capillary

Question 45

colloid osmotic pressure

Answer 45

force related to the tonicity of a solution➡️ pulling force
capillary colloid osmotic pressure
due to the prescense of solutes within the plasma that are unable to diffuse out to capillary
these solutes pull fluid back into the capillaries at the venous end of the bed

Question 46

capillary bulk flow

Answer 46

the difference between the push and pull forces determines net fluid loss from or gain to capillaries
net filtration pressure= push-pull

Question 47

oedema

Answer 47

abnormal ⬆️ in volumes of interstitial fluid
due to an ⬆️ push, ⬇️ pull force:
increased capillary hydrostatic pressure
high blood volume, local vessel blockage, incompetent venous valves
inflammation➡️ causes increased capillary permeability
decreased colloid osmotic pressure
low levels of plasma proteins due to liver disease or malnutrition
blockage of lymphatic vessels➡️ preventing fluid drainage from tissues
parasites, surgical removal

Question 48

oedema

Answer 48

abnormal ⬆️ in volumes of interstitial fluid
due to an ⬆️ push, ⬇️ pull force:
increased capillary hydrostatic pressure
high blood volume, local vessel blockage, incompetent venous valves
inflammation➡️ causes increased capillary permeability
decreased colloid osmotic pressure
low levels of plasma proteins due to liver disease or malnutrition
blockage of lymphatic vessels➡️ preventing fluid drainage from tissues
parasites, surgical removal

Question 49

oedema

Answer 49

abnormal ⬆️ in volumes of interstitial fluid
due to an ⬆️ push, ⬇️ pull force:
increased capillary hydrostatic pressure
high blood volume, local vessel blockage, incompetent venous valves
inflammation➡️ causes increased capillary permeability
decreased colloid osmotic pressure
low levels of plasma proteins due to liver disease or malnutrition
blockage of lymphatic vessels➡️ preventing fluid drainage from tissues
parasites, surgical removal

Question 50

blood vessel of the body

Answer 50

arteries are usually deep, while veins are both deep and superficial
deep veins tend to run parallel with arteries and share the same names, while superficial veins tend to have distinct names
venous pathways are more interconnected than arterial pathways
most blood vessels in the head an limbs are bilaterally symmetrical while some of the large, deep vessels of the trunk are asymmetrical or unpaired

Question 50

blood vessel of the body

Answer 50

arteries are usually deep, while veins are both deep and superficial
deep veins tend to run parallel with arteries and share the same names, while superficial veins tend to have distinct names
venous pathways are more interconnected than arterial pathways
most blood vessels in the head an limbs are bilaterally symmetrical while some of the large, deep vessels of the trunk are asymmetrical or unpaired

Question 51

major subdivision

Answer 51

pulmonary circuit:
transport blood between the -heart and lungs to facilitate gas exchange
-does not provide for the metabolic needs of the body tissues
systemic circuit
provides a functional blood supply to all the body tissues, delivering nutrients, gases and hormones to the tissues removing metabolic wastes

Question 52

major veins

Answer 52

median cubital vein, located in teh cubital fossa connects the basillic and cephalic veins
all 3 of these veins are common locations for venepuncture, particularly the median cubital vein