9. Transport in Animals Flashcards
Describe the single circulation of a fish
For every one circuit of the body, the blood which absorbs oxygen in the gills in lower-pressure, passes through the heart once
Descrbie the circulatory system
A system of blood vessels with a pump and valves to ensure one-way flow of blood
Describe the double circulation of a mammal
The heart is four-chambered, so for every one circuit of the body, the blood passes through the heart twice. The right side receives deoxygenated blood and pumps it to the lungs where blood will be oxygenated and transferred to the left side of the heart to pump it to the body
Explain the advantages of a double circulation
- Blood cannot travel as fast: The pumping of the heart reduces a lot of pressure in capillaries of the lungs
- Respiration is faster: As blood from the lungs can increase pressure before being sent to the body, cells are supplied with oxygen and glucose require
Where is blood pumped away from the heart and to the heart
Blood is pumped away from the heart in arteries and returns to the heart in veins
State how the activity of the heart may be monitored by
ECG, pulse rate and listening to sounds of valves closing
Investigate and describe the effect of physical activity on the heart rate
- Investigation: Consistently measuring the breathing rate (count the number of breaths per minute) and heart rate (taking a pulse) before and after an activity is performed
- Describing: Increase of physical activity increases breathing rate and heart rate. The heart rate remains high for a period of time; once the physical activity has stopped, there’s a gradual return to resting heart rate
Describe coronary heart disease
Plaque from cholesterol/white blood cells builds up in the coronary artery (at cardiac muscle), the artery loses elasticity, and therefore can’t stretch to accommodate the (forcing) blood, restricting blood flow
Discuss the roles of diet and exercise in reducing the risk of coronary heart disease
- Diet: Reduce animal fats, and eat more vegetables and fruits to reduce weight + cholesterol level in the blood
- Exercise regularly: Reduces weight, cholesterol levels, blood pressure, and stress
State the possible risk factors of coronary heart disease
- Age
- Diet
- Lifestyle
- Sex
- Genetic predisposition
- Smoking
- Lack of exercise
Explain the relative thickness of:
(a) the muscle walls of the left and right ventricles
(b) the muscle walls of the atria compared to those of the ventricles
a) The muscle walls of the left and right ventricles: Left ventricle has to pump blood at high pressure around the entire body, therefore it has a thicker muscle wall than the right. Right ventricle has to only pump blood at lower pressure to the lungs.
b) The muscle walls of the atria compared to those of the ventricles: Atria’s muscle walls are less thicker than the ventricles since the role of the ventricles is to pump blood out of the heart which requires a high pressure
Explain the importance of the septum in separating oxygenated and deoxygenated blood
Septum separates the sides of the heart, and so prevents oxygenated and deoxygenated blood from mixing
Describe the functioning of the heart in terms of the contraction of muscles of the atria and ventricles and the action of the valves
- Entering the heart: From the right side, deoxygenated blood enters the vena cava, flowing to the right atrium.
- Heart pumps: When the right atrium is filled, the heart gives a beat, pushing blood through the tricuspid (atrioventricular) valve into the right ventricle.
- Right ventricle walls contract: For blood to be pushed into the pulmonary artery through the semilunar (atrioventricular) valve, preventing blood from flowing backward into the heart.
- Passage of the blood: Enters the lungs → capillaries → alveoli, where gas exchange occurs (the right side of the heart needs low pressure as blood is going directly to the capillaries, which could burst if high pressure).
- Returning: Oxygen-rich blood flows into the pulmonary vein, returning to the left atrium, through the bicuspid valve, and into the left ventricle.
- Left ventricle walls contract: Strongly to forcefully push the blood through the semilunar valve (prevents the backflow of blood) and into the aorta, where blood is passed around the body.
Explain the effect of physical activity on the heart rate
- So that sufficient blood is provided to the working muscles, with nutrients and oxygen for increased respiration
- Following exercise, the heart beats faster allowing excess waste products on the muscle cells to be removed
- And to ensure that extra oxygen is still being delivered to the muscle cells, to breakdown built-up lactic acid in cells from anaerobic respiration
Describe the structure of arteries, veins and capillaries, limited to: relative thickness of wall, diameter of the lumen and the presence of valves in veins
- Arteries: Thick, muscular walls with elastic fibers, narrow lumen, no valves (✖)
- Veins: Thin walls compared to arteries, wide lumen, valves present (✔) to prevent backflow
- Capillaries: One cell thick walls (with gaps for fluid to leak out), very narrow lumen, no valves (✖)
State the functions of capillaries
Within body tissues where exchanging of substances occurs
- One cell thick wall: Allows easy diffusion of substances entering and exiting the cell
- ‘Leaky’ walls: For plasma to leak out and form tissue fluids surrounding cells
Explain how the structure of capillaries is related to their functions
- One cell thick wall: Allows easy diffusion of substances entering and exiting the cell
- ‘Leaky’ walls: For plasma to leak out and form tissue fluids surrounding cells
Identify in diagrams and images the main blood vessels to and from the:
(a) heart, limited to: vena cava, aorta, pulmonary artery and pulmonary vein
(b) lungs, limited to: pulmonary artery and pulmonary vein
(c) kidney, limited to: renal artery and renal vein
- General: Transportation of blood: Away from the heart and towards organs in arteries → narrows to arterioles → capillaries → passes to organs; → widens to venules → veins moves away from the organs and → back towards the heart
- Arteries carry oxygenated blood, veins carries deoxygenated blood
Identify, in diagrams and images, the main blood vessels to and from the liver as: hepatic artery, hepatic veins and hepatic portal vein
Blood vessels to and from the liver: Oxygenated blood from the heart → hepatic artery → deoxygenated blood from the liver → hepatic vein → to the heart; deoxygenated blood from the gut → hepatic portal vein → liver
List the components of blood
red blood cells, white blood cells, platelets and plasma
State the functions of the components of blood
- Red blood cells: Transports oxygen for aerobic respiration throughout the body in the form of oxyhaemoglobin
- White blood cells: Defends the body from pathogens by carrying out phagocytosis and antibody production
- Platelets: Helping the blood to clot (blood clotting)
- Plasma: Transports carbon dioxide, nutrients, urea, mineral ions, hormones and heat energy
State the functions of: lymphocytes and phagocytes
a) Phagocyte (left): Carries out phagocytosis by engulfing pathogens and digesting them with digestive enzymes. They detect chemicals of the pathogens by their sensitive cell membrane, detecting and engulfing them in the phagosome, releasing digestive enzymes
b) Lymphocyte (right): Produces antibodies (complimentary to specific antigen on pathogens) to destroy pathogens by binding it with the antigen on pathogens; and antitoxins to neutralise its toxins
State the roles of blood clotting
Prevent continuous/significant blood loss and the entry of pathogens
Describe the process of clotting as the conversion of fibrinogen to fibrin to form a mesh
- Platelets (fragments of cell) accumulate: At the open wound to stop the bleeding
- Reactions occur within the blood plasma, releasing fibrinogen proteins
- Fibrinogen (soluble) converts to fibrin (insoluble): By chemicals released from platelets
- Clot is formed: As fibrin forms an insoluble mesh across the wound, trapping red blood cells
- Hardens to a scab: Sealing the wound over time until new skin grows underneath, preventing entry of bacteria
