C&b 071 & 079 Central Nervous Control Of The Circulation: Significance In Health And Disease I & Ii

Front 1

What is 'pulse pressure'?

Back 1

The pressure difference between the systolic and diastolic pressures

Front 2

When one becomes older, blood pressure increases due to reduced elasticity of the blood vessels. What is the name for this increased rigidity and what does the heart rate rise to?

Back 2

Arteriosclerosis
180/90 mmHg

Front 3

What is the name for high blood pressure? What defines it?

Back 3

Hypertension. Diastolic > 90 (stage one) or 100 (stage two) mmHg

Front 4

What is MAP? Definition and calculationS

Back 4

A term used in medicine to describe an average blood pressure in an individual

CO x TPR
and
2(DP)/3 + (SP)/3

Front 5

What are the principal regions of the CNS that are concerned with the control of the cardiovascular system?

Back 5

Hypothalamus and medulla oblongata

Front 6

What is the name for the areas of the medulla oblongata that are concerned with the control of the cardiovascular system?

Back 6

The cardiac control centres (However, this is misleading as medullary neurones are controlled by higher brain areas)

Front 7

Afferent information concerning the pressures within the circulation is supplied by two groups of receptors. What are their names?

Back 7

High pressure receptors (baroreceptors)
--> Found in aorta and carotid bodies

Low pressure receptors (volume receptors)
--> Found in the walls of the atria and ventricles

Front 8

Are volume receptors high, or low pressure receptors?

Back 8

Low! Baroreceptors are high (volume receptors are in the walls of the atria and ventricles)

Front 9

Where are the baroreceptors located?

Back 9

In the aorta and carotid bodies

Front 10

Which pressure receptors are located in the aorta and carotid bodies?

Back 10

The baroreceptors

Front 11

Where are the volume receptors located?

Back 11

In the walls of the atria and ventricles

Front 12

When pressure drops in the atria, indicating a drop in blood volume, a signal is sent from the atrial volume receptors to the hypothalamus. The hypothalamus, in turn, stimulates the production of vasopressin (ADH)

Back 12

Vasopression is a vasoconstrictor and can raise BP

Front 13

How does vasopressin fit into the control of circulation?

Back 13

It is released when the volume receptors in the walls of the atria and ventricles detect a drop in blood volume and send a message to the hypothalamus. It increased causes vasoconstriction and hence increases BP

Front 14

It is released when the volume receptors in the walls of the atria and ventricles detect a drop in blood volume and send a message to the hypothalamus. It increased causes vasoconstriction and hence increases BP

Back 14

Vasopressin

Front 15

Which pressure receptors are located in the walls of the atria and ventricles?

Back 15

Volume receptors

Front 16

What two different pieces of information are relayed to the brain by the volume and baroreceptors?

Back 16

Cardiac filling pressure and arterial pressure

Front 17

What is the effect of stimulating arterial baroreceptors with respect to heart rate and vasomotion?

Back 17

Vasodilation takes place and heart rate decreases.

Front 18

What are the two regulatory mechanisms for maintaining arterial blood pressure?

Back 18

Rapid regulation --> Nerves and hormones

Longer term --> Control of blood volume (largely mediated by kidney)

Front 19

The baroreceptors are mechanoreceptors that sense the degree of _______ of the walls of the vessels (e.g. aorta)

Back 19

Stretch

Front 20

Impulses from the baroreceptors are transmitted to the brainstem where they terminate in the...

Back 20

Nucleus of the tractus solitarius (NTS)

Front 21

Afferents from the aortic arch baroreceptors travel in the ______ nerve which then merges with the _____ nerve

Back 21

Aortic nerve, which merges with the vagus nerve

Front 22

Afferents from the carotid sinus baroreceptors are carried by the _______ _____ nerve which merges with the ________________ nerve

Back 22

Caortid sinus nerve which merges with the glossopharyngeal

Front 23

At normal levels of blood pressure, do the baroreceptor afferents, or efferents show tonic activity?

Back 23

The baroreceptor afferents

Front 24

What is the baroreceptor reflex?

Back 24

The changes in peripheral vascular tone and in the force and rate of cardiac contraction that occur in response to changes in baroreceptor activation

Front 25

'The changes in peripheral vascular tone and in the force and rate of cardiac contraction that occur in response to changes in baroreceptor activation' describes what?

Back 25

The baroreceptor reflex

Front 26

The reflex vasomotor responses occuring in response to a change in blood pressure are due entirely to alterations in the frequency of discharge in ___________ vasoconstrictor fibres. ___________ vasodilator fibres are not involved

Back 26

Sympathetic

Front 27

What property of baroreceptors makes them ineffective monitors of the absolute pressure of the blood and only effective as short term regulators?

Back 27

After 15 minutes of raised arterial blood pressure, the threshold for baroreceptor activity rises to a higher value (NB they can be resent again)

Front 28

When a person moves quickly from a lying down to a standing position, there is a significant increase in venous return to the heart T/F

Back 28

False, there is a significant decrease

Front 29

Why is there a significant decrease in venous return to the heart when a person stands up from being prone?

Back 29

There is a sift of blood from the cardiopulmonary region to the legs

Front 30

What is postural hypertension?

Back 30

When a person moves quickly from a lying to a standing position, there is a significant fall in venous return to the heart (as a result of a shift of blood from the cardiopulmonary region to the veins in the legs). In turn, this leads to a fall in stroke volume (by Starling's Law), cardiac output, and therefore blood pressure.

This is known as postural hypertension

Front 31

'When a person moves quickly from a lying to a standing position, there is a significant fall in venous return to the heart (as a result of a shift of blood from the cardiopulmonary region to the veins in the legs). In turn, this leads to a fall in stroke volume (by Starling's Law), cardiac output, and therefore blood pressure.'

What is this effect known as?

Back 31

Postural hypertension. The baroreceptors play an important role in the rapid restoration of normal blood pressure

Front 32

'An attempt to expire against a closed glottis' is known as the...

Back 32

Valsalva manoeuvre

Front 33

What is the Valsalva manoeuvre?

Back 33

An attempt to expire against a closed glottis

Front 34

Hormonal control of blood volume provides long-term/short term regulation of blood pressure

Back 34

Long-term (?from Kidneys)

Front 35

What are the chief mechanisms of maintenance of a constant circulating volume?

Back 35

Chiefly hormonal:

Reflex control of pituitary ADH secretion by osmoreceptors in theh ypothalamus

Operation of the renin-angiotensin-aldosterone system

Role of the atrial natriuretic peptide

Front 36

Which receptors secrete ADH, and where are they located?

What is one of the important roles of ADH?

Back 36

Osmoreceptors, in the hypothalamus

Important in maintaining a constant circulating volume.

Front 37

Activation of the peripheral arterial *chemo*receptors causes an increase/decrease in blood pressure

Back 37

Increase (through vasoconstriction)

Front 38

What is respiratory sinus arrhythmia?

Back 38

During inspiration, there is a small increase in heart rate which is followed by a decrease in rate during expiration. This is respiratory sinus arrhythmia, it is normal.

Front 39

During inspiration, there is a small increase in heart rate which is followed by a decrease in rate during expiration. This is called...

Back 39

Respiratory sinus arrhythmia

Front 40

Activation of 'work receptors' elicits an increase/decrease in cardiac output

Back 40

Increase

Front 41

Where are work receptors found?

Back 41

In skeletal muscle

Front 42

This type of receptor that influences the cardiovascular system is found in skeletal muscle.

Back 42

Work receptor

Front 43

What are the two types of work receptor? What do they do?

Back 43

Chemoreceptors (respond to potassium and hydrogen ions produced during exercise)

Mechanoreceptors (Sensitive to the active tension generated within a muscle)

Front 44

This type of work receptor responds to potassium and hydrogen ions produced during exercise

Back 44

Chemoreceptors

Front 45

This type of work receptor is sensitive to the active tension generated within a muscle

Back 45

Mechanoreceptor

Front 46

What is the 'defense reaction'?

Back 46

The physiological changes that occur when an individual perceives danger.

Front 47

Is primary, or secondary hypertension the most common?

Back 47

Primary - 80% of individuals with high blood pressure fit into this group

Front 48

What are the most significant types of primary hypertension? Give the values that correspond to them

Back 48

Borderline (90-95 mmHg diastolic)
Mild (95-100 mmHg diastolic)
Moderate (100-114mmHg diastolic)
Severe (>114 mmHg)

Front 49

If *systolic* pressure exceeds ___ mmHg, it is considered hypertensive.

Back 49

160 mmHg

Front 50

It is important to remember that one reading of high blood pressure does not mean the patient is hypertensive

Back 50

A sustained period of measurement over 24 hours is ideal

Front 51

Some people show an automatic elevation in blood pressure when they are confronted by a doctor

Back 51

So called 'white coat' hypertension

Front 52

Do cases of primary hypertension have a high blood pressure with, or without evidence of other disease?

Back 52

Without, reasons why are not fully understood.

Front 53

What are some causes of primary hypertension?

Back 53

High salt intake
Excessive alcohol consumption
Stress
Use of certain types of oral contraceptives