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Medsci cardiovascular and endocrine Flashcards

1
Q

What is the measure of the cardiac output?

A

The amount of blood ejected to the aorta per minute.

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2
Q

Frank starling law of the heart

A

The more stretched the ventricles are the more forceful the contraction, the more stretched the muscle fibers in the cardiac system the more forceful the contraction will be. This ensures the amount of blood returning via the venous system is matched by the amount leaving the heart: venous return = cardiac output.

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3
Q

the heart valves are regulated by the cardiovascular centre in the brainstem (true or false)

A

false

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4
Q

The neurotransmitter used in the parasympathetic system released from the post and pre ganglionic neuron is (ANS)

A

acetylcholine, only one type of neurotransmitter.

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5
Q

Sensory input for the somatic nervous system is the (also is this voluntary or involuntary?)

A

special senses and somatic senses and voluntary movement.

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5
Q

Does the autonomic nervous system consist of a single neuron pathway or two neuron pathway

A

it is a 2 neuron pathway from the preganglionic neuron in the CNS and the postganglionic neuron located in the ganglion and extends axon to the target organ

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6
Q

Neurotransmitter(s) used in the sympathetic nervous system

A

Acetylcholine and norepinephrine. Two types of neurotransmitter. Pre ganglionic: acetylcholine, post to effector: norepinephrine. Post ganglionic to sweat glands is acetylcholine.

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7
Q

Does the somatic nervous system require 2 neuron pathway or one.

A

Single neuron pathway directly from CNS to target muscle.

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8
Q

What are the neurotransmitters used in the somatic nervous system?

A

Acetylcholine

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9
Q

what is the autonomic nervous system

A

divided into two branches, the parasympathetic and the sympathetic nervous systems. Which each use different neurotransmitters. However in the parasympathetic nervous system, acetylcholine is the dominant neurotransmitter. Whereas in the sympathetic nervous system, norepinephrine and acetylcholine are used for both pre ganglionic and post ganglionic neurons.

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10
Q

What is the neurotransmitter used for all pre ganglionic axons, post ganglionic parasympathetic neurons and post ganglionic sympathetic neurons to sweat glands

A

acetylcholine

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11
Q

What is the neurotransmitter used for postganglionic sympathetic fibres to most effector tissues

A

norepinephrine.

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12
Q

What is unusual about the venous drainage of the gut

A

Blood leaving the gut does not directly return back to the heart as it carries deoxygenated blood to the liver which is transported through a portal system (hepatic portal vein). The liver also receives oxygenated blood from the systemic circuit(artery) meaning it has a dual blood supply.

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13
Q

Where does the left atrium receive oxygenated blood from

A

pulmonary vein

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14
Q

During ventricular ejection where does the left ventricle send the oxygenated blood

A

To the aortic arch (main artery) through the now opened aortic valves.

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14
Q

What is the valve in between the right ventricle and atria

A

tricuspid valve

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15
Q

What are the pulmonary and aortic valves classed as

A

semilunar valves with three cusps that have pockets to fill with blood in order to prevent backflow. These are closed during ventricular filling and open during ejection.

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16
Q

Where does the right atrium receive its deoxygenated blood

A

from the superior and interior vena cava

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17
Q

What is the valve associated with the right atrium and ventricle

A

tricuspid valve

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18
Q

Where does the deoxygenated blood flow from the right ventricle during ejection

A

blood goes through the pulmonary valve to the pulmonary trunk toward the lungs to be reoxygenated and returned to the left atrium via the pulmonary vein.

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19
Q

what prevents the valves from inverting in the cardiovascular structure of the heart?

A

The cordae tendinae which act like parachute strings.

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20
Q

What factors affect stroke volume?

A

Preload, afterload and the contractility of the heart.

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21
Q

The apex of the heart points

A

inferiorly and anteriorly (dorsal) and toward the left

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22
Q

the divisions of the heart corresponding to the midline of the body

A

1/3 of the heart is toward the right and 2/3 of the heart is toward the left

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23
Q

The right border of the heart is mainly formed by

A

the right atrium

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24
Q

the inferior border of the heart is mainly formed by the

A

right ventricle

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25
Q

the left border of the heart is mainly formed by

A

the left ventricle.

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26
Q

Functions of the fibrous skeleton

A

Insulates the ventricular myocardium from the electrical activity of the atria and also acts as structural support for the high pressure valves of the heart.

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26
Q

The protection of the heart and the spacing order of the parietal and visceral pericardium

A

The visceral pericardium is the innermost layer, and the parietal the outermost layer. The middle consists of the pericardial space.

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27
Q

Which valve is not supported by a fibrous ring/skeleton?

A

The pulmonary valve.

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28
Q

Ventricular filling

A

Longest phase of cardiac cycle, 80% capacity as mitral valve is open.

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28
Q

What is the function of SV node

A

Acts as the pacemaker of a heart which is independent to the nervous system, allowing the heart to produce it’s own electrical impulses stimulating its contraction, without neural input from the brain/and or spinal cord.

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28
Q

Function of AV node

A

Causes a delay of action potentials traveling through the muscle of the heart. This gives the atria extra time to contract as mechanical contraction is slower than electrical conduction. This allows the a top up of volume to the ventricles prior to contraction.
Without this the atrium and ventricles would contract simultaneously.

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28
Q

conduction potential pathway

A

SA node -> Atrial myocardium -> AV node -> AV bundle (of His) -> left right bundle branches -> purkinje fibres -> ventricular myocardium.

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29
Q

The cardiac cycle

A

Ventricular filling phase -> atrial contraction -> isovolumetric contraction -> ventricular ejection -> isovolumetric ventricular relaxation.

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30
Q

pressure in right atria

A

5mmHg peak pressure

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30
Q

Pressure in left atria

A

8mmHg

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30
Q

Pressure in aorta

A

120/90 mmHg

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31
Q

Pulmonary circuit blood volume

A

9%

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32
Q

systemic circuit blood volume

A

84%

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33
Q

blood volume in the pumps of the circuits

A

7%

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34
Q

Total output of blood volume from each pump

A

5L/min on each side.

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35
Q

Total blood volume in the pulmonary/systemic circuits and pumps

A

5L

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36
Q

Portal vein between the gut and liver

A

hepatic portal vein transports the nutrients from the gut to the liver

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36
Q

why is the liver different in terms of the systemic circuit organs

A

the liver has two areas of blood supply, deoxygenated blood from the hepatic portal vein to the liver from the gut and the systemic arteries that pump oxygenated blood to the liver

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37
Q

the systemic circuit blood pressure and resistance level

A

High pressure and resistance and consists of many systems

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37
Q

the pulmonary circuit blood pressure and resistance level

A

medium resistance and pressure and the pulmonary veins carry the oxygenated blood and arteries carry deoxygenated.

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38
Q

veins are low or high pressure

A

low

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38
Q

arteries are low or high pressure

A

high

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39
Q

interventricular sulcus

A

the sulcus that divides the two ventricles apart, usually surrounded by fat.

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40
Q

maximum pressure in the right ventricle

A

27 mmHg

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41
Q

right atrial catheterization

A

1929 Dr werner Forssmann

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42
Q

max pressure in the left ventricle

A

120mmHg

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43
Q

Papillary muscles

A

passsive structures that hold up the cordae tendineae in the ventricles.

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44
Q

Inlets diameter vs outlet

A

the inlets must be of larger diameter than the outlets because blood leaves the ventricles at high pressure. Inlets are large due to passive filling.

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44
Q

Apex of the heart

A

the opposite side of the base of the heart, pointed toward the left.

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44
Q

ventricular outlet valves

A

outlet valves are classed as semilunar valves with three cusps that can fill with blood. They are passive and dont require cordae tendineae or papillary muscles and are controlled by blood flow direction.

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44
Q

Wall thickness ration of the right ventricle vs left ventricle

A

3:1 diameter

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45
Q

peak pressure ratios comparing right and left ventricles

A

5:1

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46
Q

base of the heart

A

the highest point of the heart, superior border = blood vessels = base

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47
Q

Visceral pericardium

A

attached to the heart itself, the innermost layer of pericardium

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48
Q

fibrous pericardium

A

on top of the pericardium support parietal pericardium.

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48
Q

parietal pericardium,

A

outermost layer of pericardium on periphery.

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49
Q

pericardial space

A

filled with serous fluid allows two membranes to slide and reduce friction.

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50
Q

Mesothelial cells

A

forms the serous membrane

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50
Q

serous membrane

A

secretes serous fluid

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51
Q

Layers of the heart/around heart

A

fiborous pericardium, parietal pericardium, pericardial space, epicardium/visceral pericardium, myocardium, endocardium and inside the ventricle.

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52
Q

the layer of pericardium under myocardium

A

endocardium

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53
Q

SA node signals..

A

SA node depolarises and signals through wall of atrium, telling the myocardium to contract. This causes uniform and even contraction

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53
Q

SA node and cardiac myocytes/purkinje cells

A

act like nerves of the heart and conduct signals to tell the heart to contract. Modified cardiac muscle fibers

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54
Q

SA node -> atrial muscle speed and result

A

slow and causes even atrial contraction

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55
Q

AV node

A

very slow and causes 100 millisecond delay for the atria to top up the ventricles.

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56
Q

AV bundle -> purkinje fibres

A

fast and cause complete and even ventricular contraction -> systole.

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57
Q

ventricular filling phase

A

ventricle fills to about 80% of its capacity, long phase. Mitral valve opens quietly. 5mmHg in left atrium and 90mmHg in aorta.

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58
Q

SA node can be affected by

A

hormones, sympathetic and parasympathetic nerves but also has its own natural heart rate.

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59
Q

Atrial contraction

A

SA node fires, atria start to contract and add pressure to top up missing 20% in the ventricle.

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59
Q

Isovolumetric ventricular contraction (systole)

A

AV node-> AV bundle -> wall of ventricle -> fast contraction. Super fast phase 0.05 sec. Ventricular pressure exceeds atrial pressure and both valve closes causing the first lub sound. Atrial pressure < ventricular pressure (rising) < arterial pressure.

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60
Q

Isolvolumetric ventricular relaxation

A

the ventricle relaxes, ventricular pressure drops suddenly and the flow reverses in the aorta therefore the aortic valve closes causing the second heart sound. 0.05 sec phase. Atrial P < vent P (lowering) < arterial P.

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60
Q

ventricular ejection

A

systole continues, but now ventricular pressure exceeds aortic pressure and aortic valve cusps open quietly. Blood leaves ventricle. Blood is ejected into the aorta faster than it can run off, this pressure in the ventricle and aorta continues to rise steeply but will drop off.

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61
Q

types of blood vessels

A

elastic artery, muscular artery, arteriole, capillary, venules and veins.

62
Q

elastic artery

A

very large arteries near the heart with elastic walls, they expand to store blood leaving the ventricle. Consists of many thin sheets of elastin in the middle tunic. Stretches to accomodate pump and stores ventricular contraction as elastic energy. Absorbs pressure.

63
Q

muscular artery

A

flow is proportional to the fourth power of radius, a small change in radius has a large effect on flow rate. (Vasodilates and constricts) Directs bulk blood flow, channels flow to match metabolic demands. Structure: outer tunic (tunica externa), middle tunic with smooth muscle (media tunica) and inner tunic (interna tunica).

64
Q

which tunica is the thickest in the muscular artery

A

tunica media.

65
Q

Capillaries and interstitial fluid

A

interstitial fluid bathes all cells, blood plasma leaks out and form tissue fluids in the interstitial fluid. Fluid is driven out by hydrostatic pressure when capillaries lose fluid is reclaimed back to capillaries. Net loss is replenished by lymphatic drainage system that take excess fluid back to the venous system.

65
Q

Capillary

A

thin walled to allow exchange of gases, nutrients and wastes between blood and surrounding tissue fluid. Most of the lost plasma is immediately recovered due to an osmotic gradient. Diameter wide enough to admit one red blood cell. Single layer of endothelium. No smooth muscle.

65
Q

arteriole

A

lead into capillary beds and controlling pressure inside the capillary beds. Consists of endothelial cells, smooth muscle layers. They have a thicker muscular wall relative to their size than any other blood vessel. Constriction affects total peripheral resistance and in turn affects mean arterial blood pressure.

66
Q

venule

A

little vein, low pressure vessels which drain capillary beds, site for white blood cells. Lumen bigger to allow really slow flow for white blood cells to enter and attack bacteria in tissue alongside.

66
Q

vein

A

thin walled, lower pressure vessels which drain blood back to the atria, walls are thin and soft and stretch easily for vasodilation and constriction. 64% of blood volume occurs in systemic veins and venules compared to 13% in systemic arteries and arterioles.

67
Q

what is the biggest reseivor for blood

A

veins

68
Q

Coronary arteries

A

ordinary muscular arteries but supply the heart itself, these arise from the aorta just downstream of aortic valve and supply myocardium. Bringing oxygenated blood.

69
Q

deoxygenated blood is drained from the myocardium by the…

A

cardiac veins which return the blood to the right atrium.

69
Q

Severity of coronary arteries.

A

Disease severity dependent on area affected. If affected running down the ventricular septum -> creates rhythm problem. Muscular arteries prone to disease.

69
Q

Coronary artery narrowed

A

if narrowed around 20% its normal cross section by atheroma, significant obstruction to blood flow occurs, during exercise the diseased artery runs low on oxygen (ischemia) and causes chest pain (angina). Severe ischemia results in death (infarction.)

69
Q

Smaller branches of coronary arteries penetrate the myocardium

A

keeping the heart alive, needing a good supply of O2 and nutrients.

70
Q

atherosclerosis

A

too much cholesterol in a high lipid diet, closing the lumen of the vessels.

71
Q

cardiac output (mls/min-1)

A

heart rate (beats/min) x stroke volume (mls/beat)

72
Q

Heart rate normal

A

60-100 bpm controlled by SA node.

73
Q

Action potential in a ventricular contractile fibre

A

1) rapid depolarisation
2) plateau
3) repolarisation

74
Q

2) plateau

A

plateau maintained depolarisation due to Ca2+ inflow when voltage gated slow Ca2+ channels open and K+ outflow when some K+ channels open

74
Q

first step of action potential in ventricular contractile fibre

A

1) rapid depolarisation due to Na influx when voltage gated fast Na channels open

75
Q

3) repolarisation

A

repolarisation due to the closure of Ca2+ channels and K+ outflow when additional voltage gated K+ channels open.

76
Q

input to the cardiovascular center

A

higher brain centers: cerebral cortex, limbic system and hypothalamus.

76
Q

baroreceptors monitor

A

blood pressure changes input to the cardiovascular centre in the medulla

77
Q

cardiovascular output to effectors for decrease in heart rate

A

through vagus nerves (parasympathetic nerve system).

78
Q

what do vagus nerves do

A

Dominate Sa node, heart rate can be altered by turning activity up or down. Decreased rate of spontaneous depolarisation in SA and AV node which decrease heart rate.

79
Q

where is the cardiovascular center in the brain

A

the medullar oblongata.

80
Q

cardiac accelerator nerves

A

increase heart rate and contractility (sympathetic).

81
Q

vasomotor nerves

A

sympathetic, and cause vasoconstriction.

82
Q

Frank-Starling law of the heart

A

the more blood that returns to the heart during diastole, the more blood is ejected during the next systole.

83
Q

Three mechanisms that govern stroke volume

A

preload, contractility and afterload.

83
Q

preload

A

The force that stretches the cardiac muscle before contraction. As blood returns to the heart in diastole it begins to fill the ventricle -> BP rises -> stretch myocardial fibers. Increase in filling -> inc in end diastolic volume therefore inc stroke volume.

84
Q

contractility

A

The performance of the heart at a given preload and afterload -> inotropy. All factors that affect contractility act by changing the amount of calcium in cardiac muscle cells. More calcium -> inc force of contraction. High contractility -> lowers end systolic volume -> increase stroke volume.

84
Q

decreased afterload results in

A

decreased arterial blood pressure during diastole, lower end systolic volume and therefore higher stroke volume -> semilunar valves open sooner -> inc stroke volume.

84
Q

afterload

A

The amount of pressure that the heart needs to exert to eject the blood during ventricular contraction. Eg hypertension (higher aortic pressure). Increased afterload -> higher end systolic volume and therefore lowered stroke volume

85
Q

preload quote starlings law

A

the energy of contraction of the ventricle is a function of the initial length of the muscle fibers comprising its walls.

85
Q

the stroke of the left ventricle will increase as volume increases due to the myocyte stretch causing a more forceful systolic contraction.

A

preload of the left ventricle.

85
Q

positive inotropy

A

more calcium in the cardiac muscle cells, more contractility.

86
Q

negative inotropy

A

less calcium in the cardiac muscle cells, less contractility.

87
Q

increased contractility

A

pos inotropic agents -> inc sympathetic stimulation such as thyroid hormones in blood or increased calcium in extracellular fluid -> inc contractility -> inc stroke volume

87
Q

lowered contractility

A

higher end systolic volume, higher stroke volume.

88
Q

increased preload

A

increases end diastolic volume as it stretches the heart -> inc preload -> more forceful contraction and increased stroke volume

89
Q

increased stroke volume

A

increased cardiac output

90
Q

Nervous system stimulating heart rate.

A

The nervous system, as the cardiovascular center in the medulla oblongata recieves input from the cerebral cortex, limbic system, proprioceptors, baroreceptors and chemoreceptors. inc in sympathetic nervous system or decrease in parasympathetic -> inc HR

91
Q

chemicals affecting HR

A

Catecholamine/ thyroid hormones in the blood or inc in extracellular calcium increase HR.

92
Q

Physical fitness on HR

A

increased body temp inc HR

93
Q

venous return

A

the volume of blood returning to the heart from the vasculature every minute and is linked to cardiac output.

94
Q

stroke work

A

work done is equal to the change in pressure x change in volume (pressure-volume curve).

95
Q

pressure volume curve A-B

A

ventricle filling and pressure falls due to suction effects of relaxing muscle

96
Q

pressure volume curve B-C

A

pressure rises steeply but aortic valve closed so no change in volume (isovolumetric contraction phase)

97
Q

pressure volume curve C-D

A

aortic valve opens at point C and blood is ejected.

98
Q

Pressure volume curve D-A

A

aortic valve closes at D, between D and A represents isovolumetric relaxation.

99
Q

Stroke volume in a pressure-volume curve

A

40-120 in between point A and B. The width of the volume.

100
Q

What is blood pressure measured

A

BP = CO x TPR (total peripheral resistance)

101
Q

what function does blood pressure serve

A

blood pressure is the force necessary to drive blood through circulatory system and push plasma and dissolved substances from capillaries to tissues.

102
Q

Blood distribution in the cardiovascular system

A

pulmonary vessels (9%), heart (7%), systemic arteries and arterioles (13%), systemic capillaries (7%), systemic veins and venules (blood reservoirs) 64%.

103
Q

most blood distributed system in the cardiovascular system

A

veins and venules with 64%

104
Q

how much blood is distributed in the pulmonary vessels in the cardiovascular system

A

9%

105
Q

how much blood is distributed in the heart in the cardiovascular system

A

7%

106
Q

how much blood is distributed in the systemic arteries and arterioles in the cardiovascular system

A

13%

107
Q

blood pressure in various parts of the cardio-vascular system

A

pressure gradient across capillaries-> blood only flows down pressure gradient.

108
Q

how much blood is distributed in the systemic capillaries in the cardiovascular system

A

7%

109
Q

intrinsic rate of SA node cells

A

90-100 bpm

110
Q

Hydrostatic pressure

A

Hydrostatic pressure is pressure exerted by blood against walls of capillaries -> pushing fluid out to intersitital space. Higher pressure at arterial end means high hydrostatic pressure to drive solutes out.

110
Q

resting heartrate dominated by

A

parasympathetic nervous system via vagus nerve (the wanderer).

111
Q

Oncotic pressure

A

operated by plasma proteins that remain in capillaries (too large to leave). pressure drains back fluid to capillaries from interstitial space. OP relatively constant unlike hydrostatic pressure.

112
Q

transcytosis

A

vesicles of large lipid insoluble molecules (insulin which is secreted by cells (active).

113
Q

diffusion

A

solute exchange down concentration gradients

114
Q

bulk flow/filtration

A

passive movement of fluid + substances faster than diffusion alone. It is how our body sets up pressure gradients for constant movement of fluid out capillaries and aids movement of substances.

115
Q

bulk/net flow driven by

A

differences in the balance of pressure and osmotic gradients.

116
Q

What sets up the pressure gradient for the hydrostatic gradient?

A

blood pressure

117
Q

how does bulk flow allow larger molecules to travel to tissues?

A

Larger molecules like glucose are harder to move via passive diffusion therefore bulk flow active processes moves these molecules to our tissues faster to meet demand.

118
Q

osmotic pressure in capillaries

A

same pressure at around 26 mmHg

119
Q

lymphatic system (movement of fluid to circulation)

A

clears extra interstitial fluid from around organs and returning extra fluid to circulation.

120
Q

venous end of the capillary

A

26 mmHg vlood colliod osmotic pressure higher than blood hydrostatic pressure of 16 mmHg which promotes reabsorption of net pull.

121
Q

Arteriole end of the capillary

A

pressure 35 mmHg which is higher than blood colloid osmotic pressure (26 mmHg) therefore promotes fluid moving out capillary as filtration.

122
Q

net filtration pressure NFP equation

A

(BHP + IFOP) - (BCOP + IFHP). dependent on which end is measured

123
Q

Arterial end arrows

A

big arrow up BHP (35mmhg), arrow down BCOP (26 mmHg) small up IFOP (1mmhg).

124
Q

Venous end arrows

A

IFHP (interstitial fluid hydrostatic pressure) 0 (small arrow down), BCOP blood colloid osmotic pressure (26) big arrow down, and arrow up BHP (16mmhg).

125
Q

How much fluid is reabsorbed in the capillaries

A

around 85%

125
Q

arterial end interstitial fluid osmosis or hydrostatic pressure?

A

osmotic pressure

126
Q

venous end osmotic pressure or hydrostatic pressure (in capillaries)

A

hydrostatic pressure

127
Q

How can we match blood flow supply and demand?

A

we can redirect blood flow from organs that dont need as much blood via vasoconstriction. Change in radius can change flow in large amount.

128
Q

Why is blood flow/circuit built like that (parallel not vertical).

A

blood flow/circulatory structure cannot be in a series but parallel to distribute arterial pressure and venous pressure evenly across organs.

128
Q

relationship between capillaries and lymph vessels

A

Lymph vessels are close to the arterioles and venules, which help collect extra interstitial fluid and flows back up to replenish circulatory system of lost fluid.

129
Q

How does the body cope with hemorrhage (challenges to homeostasis).

A

Vasoconstriction of systemic and local blood vessels to try maintain blood pressure, Hr increase via sympathetic NS. Maintain stroke vol via inc in contractility, SNS. Inc in venous return to cope for losing blood. (inc preload).

130
Q

for capillary exchange to work

A

every cell in the body needs to be within 2 cells. Velocy roughly equates to 1/cross section area

131
Q

Flow is proportional

A

to the slope of pressure gradient and the radius of the tube it is trying to flow through

132
Q

Flow equation

A

radius ^4.

133
Q

what is a vital target for adjusting and redistributing blood flow around the body

A

vascular resistance.

134
Q

Hemodynamic regulation of flow

A

constriction and dilation of arterioles, capillaries and venules. Precapillary sphincters can constrict and force blood through a direct pathway and prioritise a route.

135
Q

precapillary sphincters

A

bands of smooth muscles before capillaries that can relax or constrict depending on where blood flow needs to be prioritised.

136
Q

Where are baroreceptors located

A

aortic arch or carotid sinuses

137
Q

what do baroreceptors respond to specifically

A

stretch in arterial wall therefore hydrostatic pressure, as organs stretch more.

138
Q

Where are baroreceptors connected to and how are they activated.

A

they connect sensors up to the brain via crainal nerves and can respond to changes in blood pressure as they are tonically active (PSNS AND SNS)

139
Q

Baroreceptors sensory to CV centre route

A

sensory info comes in and is processed to determine how fast sympathetic nerves fire, neurons terminate in medulla of the cardiovascular center.

140
Q

VASODILATION HORMONES

A

atrial natriuretic peptide, epinephrine, nitric oxide, decrease blood pressure.

141
Q

Cardiovascular center is also a place for what type of cell bodies?

A

autonomic nerves.

142
Q

CARDIAC OUTPUT REGULATION VIA HORMONES

A

NOREPINEPHRINE AND EPINEPHRINE (ADRENALINE/SYMPATHETIC) to increase HR and contractility + BP

143
Q

VASOCONSTRICTION HORMONES

A

ANGIOTENSIN II + NOREPINPHRINE + EPINEPHRINE increase blood pressure.

144
Q

BARORECEPTOR REFLEXES FULL BREAKDOWN

A

stimulus (BP high) -> baroreceptors in carotid sinus or arch of aorta -> input (stretch less dec rate of nerve impulse) -> control centers (CV center in medulla or adrenal medulla) -> output (response) -> effectors (heart/blood vessels) -> response.

144
Q

BLOOD VOL INCREASE HORMONE

A

increase BP, aldosterone, antidiuretic hormone.

144
Q

Tonicity- vascular tone

A

increase and decrease based on sympathetic input, higher levels of norepinephrine bind to alpha receptor on arteries (or anything with smooth muscle) and causes constriction, however lower concentrations cause vasodilation.

145
Q

BLOOD VOL DECREASE

A

decrease BP, atrial natriuretic peptide.

146
Q

vasodilation affect on total peripheral resistance

A

lowers TPR

147
Q

what are the control centres for blood pressure

A

cardiovascular center in the medulla oblongata or the adrenal medulla.

147
Q

increased number of red blood cells (polycythemia)

A

increase blood viscosity-> decreased blood vessel radius (vasoconstriction) -> increased systemic vascular resistance -> increase blood pressure

148
Q

increased body size (obesity)

A

increased total blood vessel length -> inc systemic vascular resistance -> high blood pressure

149
Q

systemic vascular resistance

A

resistance that blood must overcome to flow through the systemic circulation

150
Q

Factors that increase venous return

A

increased blood vol, skeletal muscle pump, respiratory pump, venoconstriction.

151
Q

factors that increase HR and SV -> CO and therefore BP

A

Decreased parasympathetic impulses, increased sympathetic impulses from hormones and adrenal medulla.

152
Q

increased venous return

A

increased stroke volume -> cardiac output -> mean arterial pressure (BP) inc.

153
Q

Negative feedback systems to restore normal blood pressure during hypovolemic shock - haemorage.
OTHER BARORECEPTORS.

A

carotid sinus + aortic arch -» decrease rate of nerve impulses -> control centers in hypothalamus + posterior pituitary + CV in medulla -> ADH in blood from pituitary and increased sympathetic stimulation from adrenal medulla -> effectors (kidneys, blood vessels, heart) -> response inc blood vol as kidneys conserve salt + water -> vasoconstriction -> HR + contractility inc -> INC BP.

153
Q

Negative feedback systems to restore normal blood pressure during hypovolemic shock - haemorage. KIDNEY BARORECEPTORS.

A

receptors (baroreceptors in kidneys) - juxtaglomerular cells -> kidney baroreceptors increase secretion of renin-> outputs angiotensin II in blood -> effector adrenal cortex -> liberates aldosterone -> kidneys conserve salt and water -> increase blood vol and BP.

154
Q

baroreceptors in kidneys

A

juxtaglomerular cells

155
Q
A
156
Q
A
157
Q
A
158
Q
A
159
Q
A

uni (7 decks)

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