Circulatory System in Animals

Transport in Animals

• Components of the human circulatory system: Heart, blood vessels, blood
• Heart: Muscular pump made of cardiac muscle, keeps contracting continuously.
• Heart function: Pumps blood around the body to supply cells with nutrients and oxygen, and remove waste products.
• Heart activity: Monitored by ECG and listening to valve closing sounds (Lub-Dub).
• Rhythmic sounds: Caused by valve closure (Lub - closure of atrioventricular valves; Dub - closure of semi-lunar valves in aorta and pulmonary artery).
• Heart beats: Ripple of pressure down artery, rate = pulse rate.
• Blood pressure: Pressure created by blood flow during heartbeats, measured by sphygmomanometer. Normal blood pressure is 120/80 mm Hg (systolic/diastolic).
• How to measure pulse: Place fingers on wrist, feel pulse, count pulses per minute, repeat multiple times for average.

How to measure blood pressure

• Use the first two fingers of your right hand and lie them on the inside of your left wrist.
• Feel the tendon near the outside of your wrist, then you can feel the artery in your wrist pulsing your heart pumps blood through it.
• Count the number of pulses per minute.
• Repeat this step and take the average for accuracy.

Components and adaptations of the human heart

• Chambers: Two thin-walled atria (upper) and two thick-walled ventricles (lower). Left ventricle thicker than right for more forceful blood pumping.
• Valves: prevent backflow of blood. Atrioventricular valves are between atria and ventricles (tricuspid/mitral/bicuspid). Semilunar valves are between the ventricles and arteries (aortic/pulmonary). Valves close to prevent backflow.
• Valves function: Allow blood to flow in one direction.

Coronary arteries

• Supply blood to heart muscle (needs constant supply of oxygen).
• Importance: Heart muscle needs energy to contract and relax

Important questions & answers regarding CHD

• What is CHD?: Narrowing or blockage of coronary arteries leading to heart attack.
• Reasons for CHD?: Smoking, high salt intake, high levels of saturated fats/cholesterol, lack of exercise.

Treatment of CHD

• Improving lifestyle (CHD treatment): Diet alteration (low in saturated fats and salt), exercising, and quitting smoking.
• Drugs: Statins (lower cholesterol), anti-hypertensive drugs (lower blood pressure), aspirin (reduce risk of blood clots).
• Bypass surgery: Replace damaged coronary artery with a section of blood vessel taken from another part of the body.
• Angioplasty: Narrowed coronary artery widened using a non-inflated balloon (stent) and then inflated with water.

Blood circulation

• Pulmonary circulation: Deoxygenated blood pumped from the right ventricle to the lungs, oxygenated blood returned to the left atrium.
• Systemic circulation: Oxygenated blood pumped from the left ventricle to the body, deoxygenated blood returned to the right atrium.
• Single circulation: Blood passes through the heart once per complete cycle (e.g., fish).
• Double circulation: Blood passes through the heart twice per complete cycle (e.g., humans, birds, reptiles).

Explore the human circulatory system, including the heart, blood vessels, and how they function to supply nutrients and oxygen. This quiz covers heartbeats, blood pressure measurement, and sounds generated during heart activity. Test your knowledge on the anatomy and physiology of transportation in animals.