circulatory system

Question 1

2 main parts of the circulatory system

Answer 1

pulmonary and systemics circuits

Question 2

blood flows…

Answer 2

unidirectionally in the body through and the heart

Question 3

Endothelium - blood vessels

Answer 3

common, inner cell lining, single cell layer thick

Question 4

Elastic tissue - blood vessels

Answer 4

stretch, extend and come back to shape, in veins and arteries

Question 5

Smooth muscle - blood vessels

Answer 5

contraction and relaxation of blood vessels, maintain pressure within the system
main component of arteriole

Question 6

Fibrous tissue - blood vessels

Answer 6

Provides structure
main component of venule

Question 7

Arteriole

Answer 7

resistance vessels within the body, tightly regulated, regulation of blood to underlying tissue

Question 8

Capillaries

Answer 8

where exchange occurs (gasses)

Question 9

pulmonary circulation

Answer 9

1st circulation
Blood from heart > gets oxygenated in lungs > returns to heart

Question 10

Oxygenated blood leaves heart via

Answer 10

aorta (largest): thick muscular structure - relates to pressure
Blood goes everywhere

Question 11

systemic circulation

Answer 11

2nd circulation
Takes oxygenated to blood to the rest of the body

Question 12

Arteries

Answer 12

Away from heart

Question 13

Veins

Answer 13

Return to heart

Question 14

Circulation and how blood flows

Answer 14

Typical Artery > arteriole > capillary bed > venule > vein
Portal systems: additional filtration

Question 15

What is blood?

Answer 15

It is a connective tissue made up of cellular elements, suspended in a fluid matrix
transport O2

Question 16

blood composition

Answer 16

92% water
7% protein
1% dissolved organic molecules

Question 17

cellular elements of blood

Answer 17

RBC
WBC
Platelets

Question 18

types of WBC

Answer 18

Lymphocytes
Monocytes
Neutrophils
Eosinophils
Basophils

Question 19

Erythropoiesis

Answer 19

Controlled by the glycoprotein erythropoietin (EPO) + some cytokines
* Produced by the kidneys
* The trigger for EPO release is hypoxia (low blood O2 lvls)

Question 20

Blood doping

Answer 20

Used to improve athletic performance by artificially improving the body’s ability to transport O2 to the tissues/muscles
Three common types:
1. Blood transfusion
2. Injection of EPO
3. Injection of synthetic O2 carriers

Question 21

Heart

Answer 21

The workhouse of the body:
Generates a pressure to force blood continuously around the body
Composed predominantly of cardiac muscle

Question 22

Tricuspid valve

Answer 22

3 cusps
Stops blood backflow from right ventricle into the right atrium

Question 23

Bicuspid valve

Answer 23

2 cusps
Stop blood flowing backwards from left ventricle into left atrium

Question 24

Aortic semilunar valve

Answer 24

3 cusps
determine the passage of blood between the ventricles and the main arteries, transporting blood away from the heart to the vital organs

Question 25

How does the heart contract?

Answer 25

Specialised cells within the heart generate an electrical signal to coordinate contraction 1. Sinoatrial node (S node) 2. Atrioventricular node (AV node) - down Bundles of His 3. Purkinje fibres Depolarises the membrane, spreading rapidly throughout the conducting pathway

Question 26

Systole

Answer 26

**pressure** in the **arteries** when the heart has *contracted*

Question 27

Diastole

Answer 27

pressure in the arteries when the heart is fully relaxed

Question 28

Mechanical events of the heart

Answer 28

Cycles between contraction (**systole**) and relaxation (**diastole**)

Question 29

after each beat,

Answer 29

blood still remains in the heart (65mL) * never “empty” heart * protective mechanism

Question 30

stroke volume (SV)

Answer 30

the volume ejected after each contraction

Question 31

Performance is measured by...

Answer 31

cardiac output CO CO = SV X HR CO = 70 mL/beat x 72 bpm = 5.4 L/min

Question 32

HR is altered by...

Answer 32

ANS * by changes to the depolarisation of the autorhythmic cells

Question 33

Arterial system is under...

Answer 33

high pressure

Question 34

Venous system is under...

Answer 34

low pressure

Question 35

Why does blood pressure decrease as we get further away from the heart?

Answer 35

Picking up friction from blood vessel walls

Question 36

blood pressure

Answer 36

normal : 120/80 mmHg As the heart oscillates between contraction and relaxation, measurements are taken at these points * 120 mmHg is the systolic pressure * 80 mmHg is the diastolic pressure

Question 37

postural hypotension

Answer 37

* If we **don't move** our legs we *cannot* **bring blood** to the heart * **Low pressure** assoc. with the *venous* side of the circulation * Standing causes our blood to pool at the feet * If not enough blood is returning to the heart, we **faint** to “rectify” the problem * Take away effect of gravity

Question 38

Capillary transport

Answer 38

Deliver key nutrients and remove wastes from tissue

Question 39

Transcytosis (capillary trans)

Answer 39

Package within cells and move across membrane

Question 40

Bulk flow (capillary trans)

Answer 40

Mass movement of **molecules** and **water** into **interstitial fluid** Driven by pressures

Question 41

Movement between endothelium (capillary trans)

Answer 41

**Between *cells* themselves** - soluble/small/particular charge

Question 42

Continuous capillaries

Answer 42

**Leaky** junctions Allow **water** and small dissolved **solute** to pass through

Question 43

Fenestrated capillaries

Answer 43

Large pores Allow additional movement Found in the kidney, brain etc.

Question 44

Lymphatic system

Answer 44

Returned fluid lost in interstitial space back to the circulatory system Fat absorption from gut into circulation Destroy foreign pathogens