1. Circulation of blood Flashcards
Give 5 functions of the cardiovascular system
- Bulk flow of materials
- Temperature regulation
- Homeostasis
- Host defence
- Reproduction
What is the CNS involvement in the cardiovascular system?
Intergrates cadiovascular activity and functions with that of the respiratory and renal systems
How does the left side of the heart differ to the right?
The wall of the left ventricle is thicker than the right
Name the four components of microcirculation
- Arterioles
- Precapillary sphincters
- Capillaries
- Venules
In what way do blood vessels in the body vary? (6)
- Number
- Diameter
- Wall thickness
- Smooth muscle
- Elastic tissue
- Fibrous tissue
Define an arteriole and give its function
Arterioles are the smallest diameter muscular walled arteries
Define a precapillary sphincter and give its function
Precapillary sphincters are rings of smooth muscle. which control entry of blood from arteriole into each capillary
Define a capillary and give its function
Capillaries are the smallest diameter of blood vessels that allows for diffusion of waste, nutrients etc. in and out of tissues
Define a venule and give its function
Drain blood back to the larger true veins
The ultimate function of the CVS is…
…to ensure there is adequete blood flow through the capillaries of various organs
What is the function of parallel arrangement?
Allows independent regulation of blood flow to different organs and adapts to the metabolic demands of the tissue
On what side of the heart is the bicuspid/mitral valve
Left
On what side of the heart is the tricuspid valve
right
Features of atrioventricular valves (AV)
Fairly ‘flimsy’ and attched by chordae tendinae
How do valves open?
Passively
Features of semi-lunar valves
Tricuspid, heavy duty, under more stress and physical abrasion
Function of gap junctions and intercalated discs
Permit the easy transfer of ions and allows APs to spread (functional syncitium)
What is functional syncitium?
Atrial myocardium cells are elctrically connected so depolarise and contract synchronously
Effect on SAN of Sympathetic NS
Increases rate of SAN depolarisation
Effect on SAN of Parasympathetic NS
Decreases rate of SAN depolarisation
Give 2 effects of the SNS on the heart
- Increases force and rate of contraction
- controls vasculature
Give the effect of the PSNS on the heart
slows HR
NB: PSNS has no way to relax blood vessels
Describe a useful aspect of the venous syetm
Resovoir that has a high capacity for holding blood
What is the importance of endothelial cells in pathology
changes in endothelial cells underlie many disease states
How much blood is pumped through the body at rest?
5L/min (approx)
