Anatomy of the CV systems

Question 1

Describe the factors influencing the exchange of substances between blood in capillaries and the surrounding tissues

Answer 1

* diffusion resistance ( area of exchange, dictated by the capillary density) * concentration difference

Question 2

Why is adequate blood flow necessary for maintaining capillary exchange?

Answer 2

The rate of blood flow determines the concentration gradient at the capillaries. It is therefore paramount to maintain diffusion. This is known as the perfusion rate. Blood flow to the heart, brain and kidneys must be particularly high at all times.

Question 3

What is the normal cardiac output for a male at rest and during exercise?

Answer 3

At rest: 5 L/min Exercise: 25 L/min

Question 4

Does blood flow normally change to all organs?

Answer 4

No. Those which become more metabolically active, I.e. The heart and skeletal muscle require more blood flow. However, the brain does not normally become more metabolically active.

Question 5

Describe the major components of the circulatory system

Answer 5

* the heart * blood vessels * flow control I.e. sphincters * blood * capillary exchange systems

Question 6

Where is most of the blood found in an adult?

Answer 6

67% within the veins 11% within the arteries 5% within capillaries 17% within heart and lungs

Question 7

Describe the position of the heart in situ, including its borders

Answer 7

Sits within the mediastinum, anterior to the aorta. Right: right atrium Left: left ventricle Inferior: left and right ventricle Superior: right and left atrium + greater vessels

Question 8

Why might you get shoulder tip pain in pericarditis?

Answer 8

The phrenic nerves run down the lateral aspects of the heart and innervated the diaphragm. Irritation here can be perceived as shoulder tip pain as the supraclavicular nerves have the same cervical origin as the phrenic nerve (c3 and c4)

Question 9

Describe the vessels supplying the heart itself

Answer 9

Question 10

Describe th venous drainage of the heart, in particular, the location of the coronary sinus and great cardiac vein

Answer 10

Question 11

Describe th structure of cardic muscle

Answer 11

• innervated by th Autonomic Nervous System
• contains centrally locate nuclei
• branched structure
• gap junctions
• t tubule diad