Transport in mammals Flashcards
What is the primary function of the circulatory system in mammals?
transport nutrients, gases, hormones, and waste products throughout the body, and to maintain homeostasis by regulating temperature and pH.
What are the main components of mammalian blood?
- RBC
- WBC
- Platelets
- Plasma
Structure of RBC
Red blood cells are biconcave, disk-shaped cells without a nucleus.
Function of RBC
To transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.
What is the role of white blood cells?
To defend the body against infection and foreign invaders.
What is the role of platelets in the circulatory system?
To aid in blood clotting and prevent excessive bleeding.
What is plasma?
The liquid component of blood, which transports nutrients, hormones, and waste products.
Maintains blood pressure and volume
Explain the double circulatory system in mammals.
Pulmonary circulation (between the heart and lungs) and systemic circulation (between the heart and the rest of the body).
Arteries
- Thick muscular walls
- narrow lumen
- carry oxygenated blood away from the heart under high pressure.
Veins
- Thinner walls
- larger lumen
- contain valves to prevent backflow
- carry deoxygenated blood towards the heart under low pressure.
Capillaries
Very thin walls (one cell thick)
- narrow lumen
- facilitate exchange of gases
- nutrients, and waste between blood and tissues
Explain the cardiac cycle.
The sequence of events in one heartbeat, including :
- atrial systole
- ventricular systole
- diastole.
What is systole?
The contraction phase of the heart chambers, pushing blood out of the heart.
What is diastole?
The relaxation phase of the heart chambers, allowing them to fill with blood.
What are the four chambers of the human heart?
- right atrium
- right ventricle
- left atrium
- left ventricle
Blood pathway
Vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta → Body.
What is the role of the heart valves?
To prevent backflow of blood and ensure unidirectional flow through the heart.
Which nervous system components regulate heart rate?
- sympathetic (increases heart rate)
- parasympathetic (decreases heart rate) nervous systems.
What is the role of the lymphatic system in transport?
To return excess tissue fluid to the bloodstream and provide immune functions.
How do nutrients get transported from the digestive system to the rest of the body?
Via the blood, after being absorbed into the capillaries in the intestines and transported to the liver via the hepatic portal vein.
4 main valves
- Tricuspid
- Pulmonary
- Bicuspid ( Mitral )
- Aortic
Tricuspid valve
between right atrium and right ventricle.
Pulmonary valve
between right ventricle and pulmonary artery.
Bicuspid valve ( Mitral )
between left atrium and left ventricle.
Aortic valve
between left ventricle and aorta.
What is the function of the coronary arteries?
The coronary arteries supply oxygenated blood to the heart muscle (myocardium).
Pulse
stretching and recoiling of thick elastic muscular walls of the artery to maintain high blood pressure
SAN function
Initiates the heartbeat by generating electrical impulses that spread across the atria, causing them to contract
SAN
Sinoatrial node
AVN
Atrioventricular node
AVN function
Receives the impulses from the SAN, delays them to allow the ventricles to fill with blood, and then transmits the impulses to the ventricles causing them to contract
Affinity of Haemoglobin
1) CO
2) CO2
3) O2
Depends on surrounding concentration
Bohr Shift
Effect of CO2 on the affinity of Haemoglobin towards O2
Carbonic anhydrase
found in cytoplasm of RBC
