Week 3 - Lesson 1 (Part 1) Flashcards
Hemodynamics
Blood flow, motion and equilibrium under the action of external forces
-the study of blood flow or the circulation
What does hemodynamics explain?
The physical laws that govern the flow of blood in the blood vessels
What are the factors that influence blood flow? (10)
- Cardiac function
- Vessel compliance
- Peripheral resistance
- Tone of vascular musculature
- Blood viscosity
- Pattern of branching vessels and collaterals
- Vasoconstriction and vasodilation
- Exercise
- Autoregulation
- Respiration
Vessel compliance
Being able to expand and contract with pressure changes
Peripheral resistance
The ability for the vessel to change
What happens to the peripheral resistance if the vessel dilates?
It will decrease
What will happen to the peripheral resistance if the vessel is constricted?
It will increase
Blood viscosity
The resistance of blood to flow
- how think the blood is
If the blood is thick what will happen to the viscosity?
It will increase
If the blood is thin what will happen to the viscosity?
It will decrease
What does tone of vascular musculature help with?
Determining the diameter of the vessel
Vasoconstriction
Increase in blood pressure
Vasodialation
Decrease in blood pressure
Autoregulation
Constant blood flow
- cerebral and renal vessels
How does exercise effect blood flow?
The more active you are the more your body needs blood/oxygen and the faster it will flow
What does arterial physiology depend on?
Cardiac status
What is blood flow determined by? (2)
- Blood pressure
2. Peripheral vascular resistance
Heart failure
Cardiac output is insufficient to meet the needs of the body and lungs
- not longer works
Valvular dysfunction
Valves fail to function properly
- prolapsed, vegetations, regurgitation
Prolapsed
Is a condition in which organs fall down or slip out of place
Vegetations
A mass that is caused by endocarditis
Regurgitation
Leaking heart valves
- having some back flow
What causes ischaemia?
Impaired flow to left ventricular muscle
- CAD
Ischaemia
An inadequate blood supply to an organ or part of the body, especially the heart muscles
Arrythmias
Irregular heart beat
Cardiomyopathy
Problems within the heart muscle
- thickening and enlargement of chambers
Heart beat
Rhythmic contraction of the heart
Heart rate
The number of times that the heart contracts per minute
Internal pacemaker
Sino-atrial and atrio-ventricular nodes that initiates the hearts own impulses to contract
- monitors the heart beats and initiates impulses to contract
What is heart rate controlled by?
The autonomic nervous system
What makes up the autonomic nervous system? (2)
- Sympathetic system
2. Parasympathetic system
Where does the sympathetic and parasympathetic system have the highest control?
In the centres in the brain
What kind of fashion do the sympathetic and parasympathetic system act in? (2)
- Balance
2. Reciprocal fashion
