4.1 - Overview: Cardiovascular System & The Heart Flashcards
What do multi cellular organisms require from the environment?
- Nutrients
- Oxygen
Rate of diffusion of O2 and nutrients is limited by distance. How do we overcome this?
- cardiovascular system transports substances through the body
- transported by flow of blood through circulatory system
- bulk flow rather than diffusion
Explain how materials are transported throughout the body
- from external environment to tissues: nutrients, water, gases (e.g. O2)
- b/w tissues of body: wastes, nutrients, hormones
- from tissues to external environment: metabolic wastes, heat, gases (e.g. CO2)
Name the components of the cardiovascular system:
- heart: pump
- blood vessels: vasculature
- blood cells and plasma: fluid
What makes up the external anatomy of the heart?
- Pericardium
- Coronary arteries
What is the pericardium? What is it made up of?
- tough membranous sac surrounding the heart
- made up of 2 layers with a small amount of fluid between them (pericardial fluid: lubricant)
What is the function of the coronary arteries and why are they important?
- nourishes the heart muscle
- heart has a very high O2 demand: depends heavily on adequate supply of blood flow
Another term for a heart attack
myocardial infarction
The lack of blood supply to heart can lead to?
heart attack
What makes up the internal anatomy of the heart?
- left atrium: receives blood from the pulmonary veins, sends to left ventricle (O2 rich blood)
- Left ventricle: receives blood from left atrium, sends blood to body via aorta
- Right atrium: receives blood from venae cavae, sends to right ventricle
- Right ventricle: receives blood from right atrium, sends to lungs via pulmonary arteries
What are the functions of valves in the internal anatomy of the heart?
- ensures blood flow is uni-directional (one-way)
TRUE OR FALSE:
The right and left atrium both have valves at their entrances
FALSE; none have valves at entrance
Why are valves absent at the entrance of the right and left atriums?
Due to weak atrial contraction relative to ventricular contraction
What happens to veins during atrial contraction?
- veins at the entry to the heart are compressed: closes exit to the heart and reduces backflow
Where are AV valves attached?
- attached on ventricular side to collagenous cords (chordae tendinae)
- chords prevent valves from being pushed back into atrium
Name the AV valves
- tricuspid (right ventricle)
- bicuspid (mitral: left ventricle)
What are the 2 types of semi lunar valves? What are their functions?
- pulmonary
- aortic
- prevent backflow of blood into ventricles
TRUE OR FALSE:
Semi lunar and AV valves do not needs chords to brace them
FALSE:
- semi lunar valves do not need chords due to their shape
- AV valves need chords
What are the 2 pathways for blood in the cardiovascular system?
- pulmonary circuit
- systemic circuit
What makes up the pulmonary circuit?
blood vessels in the lungs and those connecting the lungs to the heart
What is the path of blood flow of the pulmonary circuit?
- right atrium, right ventricle, pulmonary arteries to lungs
- oxygenated blood return to heart via pulmonary veins to left atrium
How is blood oxygenated in the lungs?
- Lungs have small capillaries to increase O2 transfer
- small radius, high surface area: increases resistance, decrease blood pressure
What makes up the systemic circuit?
the rest of the blood vessels of the body
What is the path of blood flow of the systemic circuit?
- left atrium, left ventricle, to aorta, branches into smaller arteries, branches to capillaries throughout body
- O2 diffuses from blood in tissues into capillary beds, flow to small venules, then larger veins
How does O2 poor blood return back to the heart?
Via superior vena cava and inferior vena cava, to right atrium
TRUE OR FALSE:
Both O2 high blood and O2 low blood have high pressure
FALSE
both have low pressure
When is the blood pressure increased?
At critical points in the double cycle
