- One heartbeat lasts about 0.85 seconds and includes atrial contraction, ventricular contraction, and relaxation of all chambers.
- The first sound "LUBB" is caused by the closure of tricuspid and bicuspid valves at the start of ventricular contraction.
- The second sound "DUP" is due to the closure of semilunar valves at the start of ventricular relaxation.
- Smaller animals and newborns have faster heart rates because of higher metabolism and heat loss.
- The full sequence of contraction and relaxation in a heartbeat is called the cardiac cycle.
Definitions [13]
Define the following term:
Blood
Blood is a fluid that circulates in the heart, arteries, capillaries, and veins of vertebrate animals. It transports nutrients and oxygen throughout the body and removes waste.
Definition: Cardiac Cycle
The complete sequence of events that occurs during one heartbeat, including contraction and relaxation of the atria and ventricles, is called the cardiac cycle.
Define the Veins.
Veins are the blood vessels that carry deoxygenated (impure) blood from the body cells to the heart.
Define the Arteries.
Arteries are the blood vessels in which oxygenated blood is going away from the heart to all parts of the body.
Define the Circulatory system.
The circulatory system is a transport system moving substances throughout our body with the help of blood.
Definition: Excretory System
Organs which are concerned with the formation, storage and elimination of urine constitute the 'excretory system'.
Define the following term:
Osmoregulation
The kidney while removing wastes like urea from the blood also regulates its composition, i.e., the percentage of water and salts. This function is called osmoregulation.
Define the following term:
Micturition
Micturition is the process of expelling urine out of the body through the urethra by opening the sphincter muscles and passing urine, involving the relaxation of the sphincter muscles between the urinary bladder and urethra.
Define excretion.
Excretion is the process that biological organisms use to expel or eliminate the waste products produced by their metabolism.
Definition: Excretion
The process of removal of chemical wastes (mainly nitrogenous wastes) from the body is known as 'excretion' (ex: out, crete: flow).
or
Excretion is the process of removal of harmful and unwanted nitrogenous waste products from the body.
Define the following term:
Kidney
Kidneys are the primary excretory organs, eliminating nitrogenous wastes (chiefly urea) from the blood and throwing it out in the form of urine.
Define the following:
Excretion
During different metabolic activities taking place in our body, the body produces many substances, of which some are useful and some are useless.
The process of removing useless and harmful metabolic waste substances is called excretion.
The process of removal of chemical wastes (Mainly Nitrogenous) from the body is known as ''excretion''. It plays an important role in maintaining the homeostatic (steady-state) condition of the body.
Define the following:
Excretory organs
During different metabolic activities taking place in our body, the body produces many substances of which some are useful and some are useless.
If retained in the body the unwanted substances may become poisonous and cause much harm and in severe cases, even death. The organs which remove these unwanted and toxic substances from the body are called excretory organs.
Key Points
Key Points: Heart Beat
Key Points: Circulation of Blood in the Heart
- The cycle begins with atrial contraction (atrial systole) while the ventricles are relaxed; blood flows easily from atria into ventricles through open cuspid valves.
- As ventricles contract (ventricular systole) and atria relax, pressure closes the cuspid valves, preventing blood from flowing back into the atria.
- Chordae tendinae, attached to papillary muscles, hold the cuspid valve flaps in place and prevent their inversion during ventricular contraction.
- Blood is pushed out of the ventricles into the pulmonary artery and aorta through semilunar valves, which open under pressure from below.
- When ventricles relax again, blood tends to return, but the semilunar valves fill and close, preventing backflow into the heart.
Concepts [10]
- Blood
- Heart Beat
- Blood Circulatory System
- Circulation of Blood in the Heart (Functioning of Heart)
- Excretion
- Human Excretory System
- Transport System in Plants
- Complex Permanent Tissues
- Complex Permanent Tissue: Phloem Structure and Function (Conducting Tissue)
- Complex Permanent Tissue: Xylem Structure and Function (Conducting Tissue)
