1. The third component in circulatory system is the Heart.
2. The Human Heart;
- made up of myogenic cardiac muscles.
- has 4 chambers; 2 atria, 2 ventricles.
- you should know: the flow of blood through the heart - refer your notes
- questions:
Why does the letf ventricle has thicker & muscular wall than the right ventricle?
What is meant by myogenic?
What are the 2 systems that can control the human heartbeat? - Circulation of blood is made possible by:
1) pumping of the heart;
2) contractions of skeletal muscles around the veins.
3. Pumping of the Heart:
- One cardiac cycle consists of 2 stages/phases: diastole & systole.
- Sino-atrial node (SA node) is the pacemaker of the heart - it initiates & coordinates heartbeat.
- SA node generates electrical impulses which causes both atria to contract.
- Atrio-ventricular node (AV node) receive the electrical impulses .... & causes both ventricles to contract at the same time.
- Artificial pacemaker helps to maintain adequate heartbeat//regulate heart rhythm in heart patient.
4. The negative feedback regulation of blood pressure -> refer your diagram.
- the receptors? baroreceptors located at the wall of the arch of aorta & carotid arteries.
- the effectors? Heart muscles & smooth muscles of blood vessels.
5. The circulatory system in insects, fish, amphibians & humans.
- you should know how to describe the type of circulation. (remember to follow the numbering & tell your story)
1) Open circulatory system (in grasshopper)
2) Single closed circulatory system (in fish)
3) Incomplete double closed circulatory system. (in frogs)
4) Complete double closed circulatory system. (in humans) - questions:
1) what is an open system? haemolymph (circulating blood-like fluid) is pumped into open vessels in a non-continuous circuit around the body//is pumped directly into the body cavity of the organism
2) what is a closed system? Blood is pumped into blood vessels & flows through closed vessels in a continuous circuit around the body.
3) What is meant by double closed circulatory system?
4) What is meant by incomplete?
6. Blood clotting mechanism -> refer to your diagram.
- you shld know these terms:
1) thrombosis, the formation of thrombus
2) embolus & embolism
3) Heart attack (MI), chest pain (angina)
4) Haemophilia
5) Coronary artery bypass surgery to treat blocked/narrowed coronary arteries. click to read more.
Should you hv any questions regarding the above, ask me during our weekly meeting.
take care.
to view animated heart, click here.
