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Flashcards in Shock Deck (54)
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1

What is the definition of blood pressure?

The pressure exerted on vessel walls by the blood

2

How is blood pressure generated?

By the ventricles ejecting blood into the arteries

3

What vessels are used to measure B.P.

Large systemic arteries such as the brachial

4

What is the main characteristic of B.P.?

It is pulsatile

5

What 3 main factors affect B.P?

1. Blood Volume
2. Vascular Resistance
3. Venous Return

6

Blood volume of an adult?

Approximately 5litres

7

What are Baroreceptors?

Pressure/Stretch Receptors

8

Where are the main baroreceptor bodies?

1. Aortic Arch
2. Carotid Arteries

9

Where is the B.P. Control centre?

Brainstem (medulla oblongata)

10

What are the two main ‘effectors’ for a change in B.P.

1. Heart
2. Vasculature

11

What are the 3 other B.P. Inputs?

- Cerebral cortex
- Limbic System
- Hypothalamus

12

What nerve is innervated to control heart rate and what nervous system is used?

Vagus nerve via parasympathetic inputs

13

What nerves increase heart rate and contractility? What Nervous system is used?

Cardiac accelerator nerves via the sympathetic nervous system

14

What nerves constrict blood vessels and what nervous system is used?

Vasomotor nerves via the sympathetic nervous system

15

What are the 4 main inputs to the CV control centre?

1. Higher brain centres
2. Propriceptors
3. Baroreceptors
4. Chemoreceptors

16

What do chemoreceptors monitor?

Gas levels in blood and CSF

17

What 3 main things do chemoreceptors monitor for?

1. Oxygen
2. Carbon Dioxide
3. pH

18

What do changes in blood composition trigger?

Homeostatic responses

19

What would an increase in CO2 and a decrease in O2 and pH result in?

Increased RR --> Increased minute ventilation to 'blow off' excess CO2 to reduce blood pH

20

What are the 5 main hormonal influences on B.P?

1. Sympathetic nervous system
2. ADH
3. ANP
4. RAA system
5. Erythropoietin

21

What effect does SNS innervation have on homeostatic mechanisms

1. Increases CO
2. Peripheral vasoconstriction

22

How does ADH attempt to conserve blood pressure?

Leads to vasocontriction --> less fluid output

23

How does ANP attempt to influence BP?

Vasodilation --> salt and water loss in urine

24

How does the RAA system attempt to conserve BP?

Aldosterone promotes water and sodium reabsorption in the kidneys which leads to an increase in vascular volume
Vasoconstriction

25

What does Erythropoietin do to conserve BP long term?

- increases RBC production
- increases blood viscocity

26

What reflex is used short term to correct BP?

Barorecpetor reflex

27

What manages BP long term?

Endocrine response

28

In blood vessels what exerts pressure inwards?

Plasma proteins

29

What process occurs at the arterial end of blood vessels?

Filtration

30

What process occurs at the venous end of blood vessels?

Reabsorption