Topic 3B – More Exchange and Transport Systems Flashcards
(42 cards)
What is the function of digestive enzymes?
Digestive enzymes break down large molecules (e.g., carbohydrates, proteins, fats) into smaller molecules that can be absorbed by the body.
What are the main digestive enzymes and their functions?
~Amylase: Breaks down starch into maltose (in saliva and pancreatic juice).
~Protease: Breaks down proteins into amino acids (e.g., pepsin in the stomach).
~Lipase: Breaks down lipids into fatty acids and glycerol (in the small intestine).
What is absorption in the context of digestion?
Absorption refers to the process where the small, soluble molecules resulting from the breakdown of food (digestion) are taken into the bloodstream and lymphatic systems.
What structures in the small intestine aid absorption?
The small intestine has villi and microvilli, which increase surface area for nutrient absorption.
What is the function of haemoglobin?
Haemoglobin is a protein in red blood cells that binds to oxygen, transporting it from the lungs to tissues and organs.
How does haemoglobin bind to oxygen?
It is a globular protein that is made up of four subunits, each containing a heme group, which binds to oxygen. The heme group contains an iron atom, which binds to oxygen in the lungs or gills and releases it in the body’s tissues.
What is the oxygen dissociation curve for haemoglobin?
A curve that shows the relationship between the partial pressure of oxygen and the percentage of haemoglobin saturated with oxygen.
How does carbon dioxide affect haemoglobin’s ability to bind oxygen?
Increased carbon dioxide levels lower blood pH, causing haemoglobin to release oxygen more readily, a phenomenon known as the Bohr effect.
What is the function of the circulatory system?
To transport oxygen and nutrients to the body’s tissues and remove waste products like carbon dioxide and urea.
What are the main components of the circulatory system?
The main components are the heart, blood vessels (arteries, veins, capillaries), and blood.
What is the difference between open and closed circulatory systems?
~Closed circulatory system: Blood is confined to vessels and circulates throughout the body (e.g., in humans).
~Open circulatory system: Blood is not contained in blood vessels and flows freely through body cavities (e.g., in insects).
What is the role of capillaries in the circulatory system?
Capillaries are small, thin blood vessels that allow for the exchange of gases, nutrients, and waste products between the blood and tissues.
What is the function of the heart?
The heart pumps blood throughout the body, maintaining blood circulation and supplying tissues with oxygen and nutrients.
How is the heart structured to carry out its function?
The heart has four chambers (two atria and two ventricles), with valves to ensure one-way blood flow and prevent backflow.
What are the two main circuits in the circulatory system?
~Pulmonary circuit: Carries deoxygenated blood from the heart to the lungs and back.
~Systemic circuit: Carries oxygenated blood from the heart to the rest of the body and back.
What is the role of the coronary arteries?
The coronary arteries supply oxygenated blood to the heart muscle itself.
How can atherosclerosis lead to heart disease?
Atherosclerosis can restrict blood flow, increasing the risk of heart attack, stroke, or other cardiovascular diseases.
What is hypertension?
Hypertension, or high blood pressure, is a condition where the force of blood against the walls of arteries is consistently too high.
How does hypertension increase the risk of cardiovascular disease?
Hypertension can damage blood vessels and the heart, increasing the risk of atherosclerosis, heart attack, and stroke.
What are the lifestyle factors that increase the risk of cardiovascular disease?
Poor diet, lack of exercise, smoking, excessive alcohol consumption, and high stress levels can all increase the risk of cardiovascular disease.
What is the function of xylem in plants?
Xylem transports water and dissolved minerals from the roots to the rest of the plant.
How does water transport occur in the xylem?
Through a combination of the cohesion-tension theory and root pressure, driven by transpiration. Water enters the roots from the soil, moves up through the xylem vessels, and is pulled upwards due to tension and cohesion. This process, driven by transpiration (water loss from leaves), helps to replace water lost through the stomata.
What are the main structural features of xylem vessels?
Xylem vessels are made of long, hollow tubes with thick, lignified walls that provide structural support and prevent collapse.
What is the function of phloem in plants?
Phloem transports organic nutrients, particularly sugars, from the leaves to other parts of the plant.
