Physiology Flashcards
What are the steps of blood moving throughout the heart?
- Deoxygenated blood enters the right atrium through the venae cavae, and moves through to the right ventricle
- Blood exits the heart through the pulmonary artery, where it then travels to the lungs to be oxygenated
- The now oxygenated blood enters the heart again through the pulmonary vein into the left atrium, and moves into the left ventricle
- This blood then exits the heart via the aorta and travels to all of the body’s tissues to supply them with O2
What are the two different types of circulatory systems and define them?
Pulmonary and Systemic circuits.
Pulmonary= the system which moves blood between the heart and the lungs to be oxygenated
Systemic= the system which moves blood between the heart and the rest of the body
What occurs when the aorta receives blood?
When the aorta receives blood there is an increase in pressure causing the vessel to increase in volume, it then retracts when the pressure drops, pushing blood forward.
What is cardiac output?
The volume of blood put out by the heart
- the blood vessels act as a hydraulic filter converting pulsatile flow to steady
How do arterioles react when blood flows from the heart?
arteries and arterioles have elastic walls so they distend when blood is ejected from the heart and recoil during diastole
Is blood flow slower in arteries or capillaries?
capillaries to ensure adequate diffusion
Where does a pulse pressure originate from?
- it is the difference between diastolic and systolic blood flow
The radial stretch of the aorta initiates a pressure wave which is later detected as a pulse
What does the velocity of flow depend on?
The cross sectional area of a tube
What occurs in Ischaemic Heart Attacks (TIA)?
A person with a constricted subclavian artery may experience a temporary lack of blood flow to the brain
- Blood speeds up to get past a constriction in the vessel, as velocity increases, pressure decreases, causing the blood to flow back down the artery
Where is most of the fluid in the human body?
- the greatest proportion of fluid is in intracellular fluid, otherwise it exists in plasma and interstitual fluid (extracellular)
How is the bulk movement of water facilitated?
- Through aquaporins
What is the difference between a semi permeable and a selectively permeable membrane?
semi- is permeable only to water, ideally
selectively- is permeable to some substances and not to others
What is diffusion vs osmosis?
Diffusion= in diffusion both solute and solvent move until solute equilibrium is reached
Osmosis= in osmosis only the solvent moves until equilibrium is reached
What does “osmolarity of a solution” refer to?
the total concentration of all solute particles
What does tonicity refer to?
the total concentration of just non penetrating solute particles
Where does water flow in osmosis?
Always from an area of low solute concentration to an area of high solute concentration
Describe the difference between
- hypotonic
- hypertonic
- isotonic
hypotonic= the concentration of non penetrating solutes is higher in the cell
hypertonic= the concentration of non penetrating solutes is higher out of the cell
Isotonic= the concentration of non penetrating solutes is equal in and outside of the cell
Are osmolarity and tonicity the same?
NO
How does Aveolar Sac structure work?
The lungs contain 600 million alveoli
- The Alveolar membrane between air and blood is extremely thin
- Therefore oxygen molecules diffuse across the membrane rapidly
- The oxygen concentration leaving the lungs is almost equal to the concentration in the alveolus
