Circulatory System Flashcards Preview

ESA 1 Body Logistics (BG) > Circulatory System > Flashcards

Flashcards in Circulatory System Deck (20)
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1
Q

What does the cardiovascular system do?

A

Circulates and transports nutrients, oxygen, carbon dioxide, hormones, and blood cells to and from cells in the body

Fights disease, stabilises temperature, pH, and helps maintain homeostasis

2
Q

Three main components of the CVS:

A

Heart, blood and blood vessels

3
Q

What is pulmonary circulation?

A

A loop through the lungs where blood is oxygenated

4
Q

What is the systemic circulation?

A

A loop through the rest of the body to provide oxygenated blood and receive deoxygenated blood.

5
Q

How much blood does an average adult have?

A

5 litres.

2 litres of red cells

3 litres of plasma

6
Q

Where is the blood distributed?

A

3.25 litres in the veins

1 litre in the heart and lungs

  1. 5 litres in the peripheral arteries
  2. 25 litres in the capillaries
7
Q

What is an end artery?

A

A terminal artery supplying all or most of the blood to a body part without significant collateral circulation.

8
Q

What is systole?

A

Left ventricular contraction causes the blood pressure in the aorta to rise to ~120mmHg. The walls of the aorta stretch.

9
Q

What is diastole?

A

The aortic semilunar valve closes. Walls of the aorta recoil maintain pressure and moving blood towards the heart. Aortic pressure drops to 70-80mmHg

10
Q

Three layers of the walls of arteries and veins:

A

Tunica intima

Tunica media

Tunica adventitia

11
Q

What is the tunica intima?

A

Endothelium

Subendothelial layer

Thick internal elastic lamina

12
Q

What is the tunica media?

A

40 layers of smooth muscle cells

Prominent external elastic lamina

13
Q

What is the tunica adventitia?

A

Thin layer of fibroelastic connective tissue

Lymphatic vessels

Nerve fibres

14
Q

What are arterioles?

A

Arteries with a diameter less than 0.1mm

Only 1-3 layers of smooth muscle in tunica media

15
Q

What are metarterioles?

A

Arteries that supply blood to capillary beds

16
Q

When is blood velocity at its lowest?

A

During passage through the capillaries

17
Q

What makes up a capillary?

A

A single layer of endothelium and its basement membrane

18
Q

What are postcapillary venules?

A

They receive blood from capillaries and are even more permeable than capillaries.

19
Q

Structural characteristics of a vein:

Compared to arteries

A

Larger diameter

Thinner wall

More connective tissue

Fewer elastic and muscle fibres

20
Q

How does venous blood get from the legs back to the heart when standing?

A

The calf muscle acts as a pump for the deep leg veins. Valves prevent a back flow.