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Y2S1 CARDIO. > Circulation > Flashcards

Flashcards in Circulation Deck (24)
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1
Q

Functions of the cardiovascular system

A

allows the bulk flow of materials:

  • gases
  • nutrients
  • hormones
  • waste

Temp regulation
homeostasis
host defence
reproduction

2
Q

how is the CVS regulated

A

Autonomic nerves and Hormones

3
Q

what is the function of the parallel arrangement of vessels

A

– Allows independent regulation of blood flow to different organs
- adapts to metabolic demands of the tissues

4
Q

aspects of the microcirculation

A

– Arterioles, precapillary sphincters, capillaries, venules

5
Q

how much blood passes through your circulation every minute

A

5 litres

6
Q

normal passage of blood

A
VC
RA
RV
Pulmonary Trunk 
Pulmonary Arteries 
Lung capillaires 
Pulmonary veins 
LA 
LV 
Aorta
Arteries 
Arterioles
Capillaries 
Venules
Veins
7
Q

Arterioles

A

– Smallest diameter muscular walled arteries

8
Q

Precapillary sphincters

A

– Rings of smooth muscle which control entry of blood from arteriole into each capillary

9
Q

Capillaries

A

– Smallest diameter blood vessel: simple tube, one cell thick, of flattened endothelial cells
– Allows for diffusion of nutrients, waste etc in/out tissues

10
Q

Venules

A

– Smallest diameter vessels which drain blood back to the larger true veins

11
Q

% of blood flow to brain

A

13%

12
Q

% of blood flow to heart

A

4%

13
Q

% of blood flow to skeletal muscle

A

20%

14
Q

% of blood Flow to skin

A

9%

15
Q

% of blood flow to kidneys

A

20%

16
Q

% of blood flow to abdominal organs

A

24%

17
Q

Atrioventricular (cuspid) valves

A

– Fairly ‘flimsy’
– Attached to chordae
tendineae and papillary muscles which stop eversion of the valves during systole

18
Q

Semiluminar valves

A

tricuspid
– More ‘heavy duty’
– Smaller openings, higher pressure  more stress and physical abrasion

19
Q

cardiac muscle cells

A

branch, and are connected together by desmosomes at the junction between cells (intercalated disks)

20
Q

intercalated disks

A

contain gap junctions that directly connect the cytoplasm and permit the easy transfer of ions between cells

21
Q

cardiac muscle features

A

Striated
– Similar to skeletal muscle
– Thick and thin filaments of myosin and actin
– Smaller fibers with individual nucleus

Connected via intercalated discs
– “Branching” of individual cells connected into a network

Electrical connection through gap junctions
– Allow passage of ions permitting action potentials to spread
– Functional syncitium

Desmosomes
– Strong, cell-to-cell adhesion molecules – Junctional complexes

22
Q

Conduction in cardiac muscle

A

Functional syncitium
– Cells of atrial myocardium are all electrically connected – Depolarise and contract synchronously
– Ventricles are similar but are a separate functional unit

23
Q

“Pacemaker” activity

A

– Sinoatrial node (SAN) is the intrinsic pacemaker – Other areas have pacemaker ability

24
Q

Autonomic innervation

A

– Sympathetic nerves increase the rate of SAN depolarisation

– Parasympathetic nerves decrease the rate of SAN depolarisation