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PHYL2062 EOS > Cardiovascular L10: Regulation of blood pressure cont. & blood composition > Flashcards

Cardiovascular L10: Regulation of blood pressure cont. & blood composition Flashcards

1
Q

What are the 3 main purposes of MAP when driving blood into tissue?

A
  1. MAP (the driving pressure head)
  2. resistance of local arterioles (which overrides sympathetic effect) (smooth muscles around- can dilate or constrict- determine how much blood gets to the organ)
  3. vascularisation/open capillaries (skeletal muscle- no smooth muscle but have sphincters at rest = 10% are open When blood isn’t required= tighten sphincter )
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2
Q

What are 5 factors that can detect and/or influence MAP?

A
  1. Baroreceptors (from horizontal to vertical (supine –> standing)) in the aortic arch &carotid sinus sensitive to pressure –> short-term (regulation of BP)
  2. Left atrial volume receptors &hypothalamic osmoreceptors –> long-term
  3. Chemoreceptors in carotid & aortic arteries sensitive to low O2 & high H+ –> short-term
  4. Cerebral cortex-hypothalamic pathway sensitive to behaviour & emotion, which influence MAP
  5. Hypothalamus sensitive to body temperature, which affects cutaneous arterioles & overrides regulation of MAP
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3
Q

Resistance in arterioles 1 and 2 _____ (increases/decreases) while CO is unchanged?

A

increases

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4
Q

What happens to flow through vessels 1 and 2?

A

Decreases (higher resistance)

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5
Q

What happens to MAP?

A

Increases (blood has to go somewhere)

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6
Q

What happens to flow through vessels 3 and 4?

A

Increases (blood needs to go somewhere)

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7
Q

Baroreceptor reflex compensates within seconds – what steps are involved in this response?

A

Describe the reflex arc- when increase in MAP

(individual steps- start corotid and aortic sinuses) systems (parasympathetic and sympathetic) and structures it innervates

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8
Q

What happens to the hydrostatic/ultrafiltration pressure in the capillaries downstream of arterioles 1 & 2?

A

related to bulkflow

decreased volume

decreased BP

decreased hydrostatic/ultrafiltration pressure in capillaries downstream of arterioles 1 and 2

Less volume = less hydrostatic pressure

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9
Q

Left atrial volume receptors & hypothalamic osmoreceptors regulate _______ responses in MAP

A

long-term changing how much volume there is

Exracellular fluid (ECF) = plasma (20%) and interstitial space (80%)

regulating ECF = regulating plasma

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10
Q

(The cardiovascular system under stress: exercise- physiological). What are 3 Marked changes occur in anticipation & at the onset of exercise?

A
  1. CO increases 2.5-fold with moderate exercise. And CO is redistributed compared to rest:
    • skeletal muscle, cardiac muscle & skin (help with losing heat) receive a greater proportion
    • other organs receive less blood flow, but brain is maintained
  2. TPR reduced due to widespread vasodilation in skeletal muscle
  3. MAP modestly increase
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11
Q

How does MAP increase in exercise? (if TPR decreased)

A

cardiac output increases = increased HR and stroke volume

MAP = TPR x cardiac output

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12
Q

(The cardiovascular system under stress: hypertension- pathological). What is the blood pressure?

A

> 140/90mmHg

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13
Q

What are the 2 broad types of hypertension?

A
  1. Primary/essential
  2. Secondary
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14
Q

What is the primary/essential broad type of hypertension?

A

unknown cause, accounts for 90% of cases, e.g. genetic, exacerbated by environmental factors

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15
Q

What is the secondary broad type of hypertension?

A

known cause & accounts for 10% of cases, e.g. kidney disease

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16
Q

Why is hypertension a viscious cycle?

A

damages vessel walls, atherosclerosis –> increased TPR (plaque built up = increase resistance = increases MAP)–> further elevates BP

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17
Q

In hypertension, baroreceptors ____ (do/don’t) return blood pressure back to normal levels –> new set-point?

A

do not

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18
Q

In hypertension, since baroreceptors don’t return blood pressure back to normal levels, there is an increased workload on heart as it is now pumping against an increased TPR. What are 5 complications?

A
  1. Left ventricular hypertrophy –> systolic heart failure
  2. Stroke (rupture of cerebral vessels)
  3. Myocardial infarction (rupture of coronary vessels) (heart attack)
  4. Kidney failure (glomerulus is being damaged too)
  5. Vision loss
19
Q

What happens in hypotension (pathological stress)?

A

Low blood volume for given vascular capacity or weakened heart (not able to inject blood into the blood)

20
Q

What is orthostatic (postural) hypotension? What does that mean?

A

transient inadequacy in sympathetic activity Lying to standing –> blood pools in lower leg veins –> reduced venous return –> reduced SV, CO & MAP –> reduced baroreceptor response –> dizziness or fainting

21
Q

What is circulatory shock (hypotension)?

A

extremely low blood pressure such that blood flow to tissues is compromised.

Causes: hypovolemic shock, cardiogenic shock, vasogenic shock, & neurogenic shock

22
Q

What are 3 features in the composition of blood?

A
  1. Blood travels within blood vessels to transport materials to cells &away from them
  2. Blood is a liquid containing plasma & suspended cellular elements
    • Erythrocytes (red blood cells)
    • Leukocytes (white blood cells)
    • Platelets (thrombocytes)
  3. It makes up ~8% of our body weight
    • 5L in women
    • 5.5L in men
23
Q

Blood travels within ______ to transport materials to cells & away from them

A

blood vessels

24
Q

Blood is a liquid containing plasma & suspended cellular elements. What are the 3 major elements?

A

Erythrocytes (red blood cells) – Leukocytes (white blood cells) – Platelets (thrombocytes)

25
Q

Blood makes up ~_______% of our body weight. (Approximately ___ L in women and ___L in male)

A

~8%; 5L; 5.5L

26
Q

_______ of the blood keeps cellular elements evenly dispersed.

A

Constant flow

27
Q

If we collect a sample & let it sit, heavier cells drop to the bottom. What is the order from bottom to top?

A

Erythrocytes; leucocytes and platelets; plasma

28
Q

______ is packed cell volume of blood. The rest is ______.

A

Haematocrit; plasma

29
Q

Plasma is 90% ______.

A

water

30
Q

What is the function of plasma?

A

It is a medium for materials being carried in blood

31
Q

What are 6 materials that are carried around by plasma (in the blood)?

A
  1. Proteins
  2. Electrolytes (Na+, Cl-, HCO3 -, K+, Ca2+, & other ions)
  3. Nutrients (glucose, amino acids, lipids, vitamins)
  4. Waste products (creatinine, bilirubin, urea)
  5. Dissolved gas (O2 & CO2)
  6. Hormones
32
Q

Plasma proteins (albumin, globulin, & fibrinogen) are not ‘just being ______’. They normally stay in plasma & have important functions. List 2 functions.

A

transported

  1. Establish a colloid osmotic gradient which prevents excessive bulk flow –> maintains plasma volume
  2. Help to buffer changes in pH
33
Q

Specifically, what is the function of albumin (plasma protein)?

A

non-specifically bind poorly soluble substances

34
Q

Specifically, what is the function of globulin (plasma protein)?

A

α and β specifically bind poorly soluble substances & blood clottng. γ are antibodies or immunoglobulins (defense)

35
Q

Specifically, what is the function of albumin (plasma protein)?

A

blood clottng

36
Q

Plasma proteins are synthesised by the _____, except antibodies which are made by type of _____ cell

A

liver; white blood

37
Q

What is the main function of erythrocytes/red blood cells?

A

O2 transport

38
Q

What are the 5 special features of erythrocytes/red blood cells?

A
  1. Flat, disc-shaped, indented in middle on both sides with flat centre: biconcave disc provides a larger surface area for O2 diffusion from plasma & into the cell
  2. Flexible membrane: deform & squeeze in single file through narrower capillaries
  3. Contain haemoglobin (pigment): O2 is poorly soluble in plasma so it is transported bound to haemoglobin, also helps to transport CO2. Reddish colour when oxygenated & bluish when deoxygenated
  4. Lacks nucleus &organelles: maximises haemoglobin content
  5. Some enzymes for metabolism (need some for energy)
39
Q

What is the 3 main function of leukocytes/white blood cells?

A
  1. elements of immune defense system
  2. Rapidly travel to sites of invasion or tissue damage
  3. Can exit blood through capillary pores by a wriggling behaviour
40
Q

What is the main function of thrombocytes/platelets? How is this done (3 ways)?

A

Haemostasis to prevent blood loss via

  1. vascular spasm,
  2. formation of platelet plug,
  3. blood coagulation
41
Q

MAP is what the body ____ and ____: the driving pressure head for blood flow to tissues

A

monitors; regulates

42
Q

MAP is determined by ___ and _____, thus all factors that influence these too

A

CO; TPR

43
Q

What are 2 short term and long term responses to regulate MAP?

A
  1. Baroreceptor reflex
  2. Left atrial volume receptors & hypothalamic osmoreceptors
44
Q

What are 2 ways that the cardiovascular system can be under stress

A
  1. Physiological (eg. exercise)
  2. Pathological (eg. hypertension and hypotension)

PHYL2062 EOS (13 decks)

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