Week 3 - Circulatory System Flashcards
Define diffusion
The net movement of molecules from a region of high concentration to low. It happens bc of random collision
How does temperature affect the rate of diffusion?
Hotter = faster
Define bulk flow
Movement of a fluid from a region of high to low pressure. The pressure gradient is determined by an external force
What is one advantage of super small animals [circ system]
Nearly every cell is in direct contact of external animal. So there is no need for a circulatory system. They rely on bulk flow to provide o2, eliminate waste
What is the difference between open and closed circulatory systems?
Open: fluid = hemolymph. It flows through open-ended vessels. The hearts keep fluid in motion to constantly wash over organs.
Closed: fluid = blood. Blood completely enclosed in vessels
Describe the travel of blood through arteries etc
Aorta, arteries, arterioles, capillaries, venules, veins, vena cava
What is systolic pressure?
Pressure generated by the contracting heart.
~120 mmHg
Name the pressure generated by the contracting heart
Systolic pressure
Name the pressure generated by the relaxed heart/the recoiling of the arteries
Diastolic
What is distolic pressure?
The pressure generated by the relaxed heart: the recoiling of the arteries
~80 mmHg
What is peripheral resistance?
The friction experienced by blood as they come into direct contact with the walls of blood vessels
Why are blood flow and pressure reduced in capillaries?
Peripheral resistance
What is the Hagen-Poiseuille equation?
Q= (deltap pi r^4)/(8lm)
m= viscocity
What is the no-slip condition?
Flow velocity of the fluid at the surface of the solid is NOT MOVING. maximum flow of the fluid is reached at some distance from the edge of the solid.
The place between max speed and no movement is called the gradient region
What is edema?
Condition caused by protein deficiency. Causes an accumulation of fluid in interstitial space
How does blood get back to the heart?
- Smooth muscles contract, forcing blood to the next section and
- one-way valves of veins prevent backflow.
- Skeletal muscles apply more pressure
What is the percentage of the body’s capillaries get blood st any given time? Why? What prevents blood from getting in capillaries?
5-10%
Blood pressure would flatline if all capillaries had blood all the time
Precapillary sphincters
What are precapillary sphincters?
Prevent blood from entering most capillaries to maintain blood pressure
How does the lymphatic system recapture fluid?
Fluid goes through lymphatic vessels to drain back into the subclavanian veins
What causes blood clots when sitting in a plane for a while?
Lack of movement so lack of skeletal muscle contraction. Doesnt squeeze veins as much. Blood can pool and clot
What separates atriums from ventricles?
Atrioventricular valves
What are the junction connecting cardiocytes called?
Intercalated disks
Name the two specialized cardiocyte clusters. What do they do?
- Sinoatrial node
Causes atria to contract in unison - Atrioventrical node
Allow ventricles to contract
What are the three stages of the cardiac cycle?
- Atrial + ventrical systole stage (0.4 sec)
- Atrial systole + ventricular diastole (0.1 sec)
- Ventricular systole and atrial diastole (0.3 sec)
How do you calculate cardiac output?
Cardiac output = heart rate (BPM) x stroke volume
What is plasma
Liquid matrix that carries proteins, antibodies, electrolytes, nutrients, etc
What is the percentage of plasma and cellular elements
plasma (55%), elements (45%)
