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Endeavour - Human Bio 2 > session 6 > Flashcards

session 6 Flashcards

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1
Q

factors affecting blood flow

A
  • vascular resistance
  • venous return (how much blood is returning to heart)
  • speed of blood flow
  • blood pressure
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2
Q

Blood pressure is

A

hydrostatic pressure exerted by blood on walls of blood vessels

Caused by ventricle contraction

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3
Q

components of blood pressure

A
  • systolic blood pressure
    • highest artery pressure during systole
  • diastolic blood pressure
    • lowest artery pressure during diastole
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4
Q

mean arterial pressure (MAP)

A
  • average blood pressure in arteries
  • MAP = diastolic BP + 1/3(systolic - diastolic BP)
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5
Q

factors affecting blood pressure

A
  • cardiac output
    • dependent on HR and SV
  • blood volume
  • vascular resistance
    • opposition to blood flow
    • caused by lumen size, thickness of blood and length of the vessel
  • elasticity of arteries
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6
Q

systemic vascular resistance (SVR)/ total peripheral resistance (TPR)

A

all vascular resistances offered by systemic blood vessels

*

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7
Q

what is venous return and how is it achieved

A
  • volume of blood flowing back to heart through systemic veins
  • depends on
    • pressure difference in venules and right atrium
    • skeletal msucle pump
      • ​contraction/relaxation of skeletal muscles
      • opens and closes venous valves
    • respiratory pump
      • ​diaphragm movement changing abdominal pressure
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8
Q

velocity of blood flow

A
  • velocity inversely related to cross sectional area of blood vessels
    • blow flows slowly whre cross sectional area is greatest
  • Blood flow decreases from aorta to arteries, is slowest in capillaries
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9
Q

circulation time

A

time for blood drop to pass from right atrium through pulmonary circulation, back to left atrium, through systemic circulation down to foot and back to right atrium

usually 1 min in resting person

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10
Q

blood pressure and blood volume are controlled by adjusting heart rate, stroke volume, blood volume and vascular resistance.

This is done thorugh several negative feedback mechanisms….

A
  • cardiovascular centre
  • nervous system
  • hormones
  • auto regulation
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11
Q

cardiovascular centre for blood flow and pressure control

A
  • group of neurons in medulla oblongata that regulate HR, contraction and vessel diameter
    • output from CV centre through
      • sympathetic impulses incresae HR and contractility
      • parasympathetic impulses along vagus nerves decrease heart rate
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12
Q

nervous system control of blood flow and pressure

A
  • nervous system regulated BP by
    • baroreceptor reflex
      • ​pressure sensitive neurons in aorta, carotid arteries
      • monitor stretch of wall
      • low BP -> low baroreceptor feedback -> CV centre increases sympahtetic stimulation -> increases HR and contractility
    • chemoreceptro reflex
      • ​monitor chemical composotion of blood ie o2, co2 and H+
      • located in carotid sinus and aortic arch
      • eg hypoxia or acidosis -> chemoreceptor stimulation -> increased sympathetic stimulation -> vasoconstriction and increased BP
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13
Q

hormonal control of BP and blood flow

A
  • renin-angiotenisin-aldosterone system
    • changes blood volume and therefore BP
  • epinephrine and norepinephrine
    • (adrenaline and noradrenaline)
    • released from adrenal medulla
  • antidiuretic hormone (ADH)
    • ​from posterior pituitary
    • causes vasoconstriction
  • atrial natriuretic peptide
    • ​released by cells in atria of heart when BP rises
    • causes vasodilation
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14
Q

autoregulation of BP

A
  • automatic adjustment to meet metabolic demands
  • physical changes
    • ​warming = vasodilation
    • cooling = vasoconstriction
  • vasodilating and vasoconstricting chemicals
    • ​vasodilators being H+, lactic acid, histamine and NO
    • vasoconstrictors being thromboxane, serotonin, endothelins
  • changes in o2 levels
    • ​systemic vessels dilate with low o2 while pulmonary vessels constrict
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15
Q

methods of checking circulation

A
  • pulse
    • created by pressure in elastic artery caused by left ventricle systole
  • blood pressure
    • measured with a sphygmomanometer
    • determines systolic and diastolic pressure
    • can hear heart sounds (korotkoff sounds)
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16
Q

what is pulse pressure

A

The difference between systolic and diastolic

17
Q

define shock

A

failure of CV system to deliver o2 and nutrients

  • negative feedback systems attempt to fix
    • eg ADH, vasodilators, renin-angiotensin-aldosterone
18
Q

disorders of homeostatic imbalance

A
  • hypertension
    • systolic above 140
    • diastolic above 90
  • results in damage to blood vessels, heart, brain and kidneys
  • managed with lifestyle changes and various drugs
19
Q

primary hypertension

A

90-95% of all hypertension cases

No known/obvious cause for persistent hypertension

20
Q

secondary hypertension

A

has a known underlying cuase

eg. obstruction of renal blood flow or damaged renal tissue

21
Q

aging and the CV system

A
  • general changes in CVS associated with aging
    • decreasled compliance of aorta
    • lowered CO and max HR
    • incresed systolic pressure
    • HDL decreases and LDL increases
22
Q

circulatory routes

A
  • systemic circulation
    • from left side of heart to rest of body and back to right side
      • coronary circ
      • cerebral circ
      • hepatic portal circ
  • pulmonary circulation
    • ​from right side of heart to lungs and back to left side
  • foetal circulation
    • ​from foetal heart through umbilical cord and back
23
Q
A
24
Q

oxygenated and deoxygenated blood

A
  • oxygenated blood
    • flows through systmeic arteries
  • deoxygenated blood
    • returns to heart through systemic veins that drain blood into superior or inferior vena cava -> right atrium
25
Q

aorta and its regions

A
  • Aorta is largest artery of the body
  • branches are
    • ascending aorta
    • arch of aorta
    • descending aorta
26
Q

branches of ascending aorta and arch of aorta

A
  • ascending = right and left coronary arteries
  • arch =
    • brachiocephalic trunk ->
      • right common carotid
      • right subclavian
    • left common carotid
    • left subclavian artery
27
Q

subclavian branches

A
  • vertebral artery
  • axillary artery
  • brachial artery
  • radial and ulnar branches
28
Q

common carotid branches

A
  • external carotid arteries
    • fro external skull structure
  • internal carotid arteries
    • for eyeballs and brain
29
Q

descending aorta composed of

A
  • Thoracic aorta
    • ​having visceral and parietal branches
  • Abdominal aorta
    • ​continuation of thoracic aorta after it passes diaphragm
    • visceral branches
      • coeliac artery
      • mesenteric arteries
    • parietal branches
30
Q

abdominal aorta segments to become

A

left and right common iliac arteries

  • these divide again into left/right external/internal iliac
31
Q

external iliac artery becomes..

A

femoral artery -> popliteal artery

32
Q

Veins can be deep or superficial. All drain blood to

A
  • superior vena cava
    • drains head and upper extremities
  • inferior vena cava
    • drains abdomen, pelvis and lower limbs
  • coronary sinus
    • drains heart muscle
33
Q

hepatic portal circulatio

A
  • carries blood between two capillary networks
  • Veins of pancreas, spleen, stomach, intestines and gallbladder -> direct blood into hepatic portal vein of liver before -> heart
    • enables nutrient utilisation and blood detoxification

Endeavour - Human Bio 2 (20 decks)

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