Excretion Chp31 Flashcards
What is the role of leaves as excretory organs in plants
plants lose oxygen and water vapour through the stomata
What is the role of the excretory system in homeostasis
regulate body temperature, control osmosis, control concentration of body fluids, remove waste products from metabolism
What are ectotherms
gain or lose heat from or to their external environment
What are endotherms
generate their own heat from metabolic reactions
Learn diagram of the skin
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What are the 3 layer in the epidermis
cornified layer, granular layer and Malpighian layer
What are the 3 layers of the skin called
epidermis, dermis and adipose tissue
What of the skin
protection, vitamin production, food store, sense organ, excretion, temperature regulation
How does the skin regulate temperature (cold)
erector muscles contract causing hairs to stand up trapping air which helps to reduce heat loss from the body and blood vessels contract reducing heat loss
How does the skin regulate temperature (hot)
sweat is produced and blood vessels expand increasing heat loss
What are the main excretory organs
lungs, skin and kidney
What are the functions of the kidneys
excretion, osmoregulation, pH control,
What organs/parts are in the urinary system
2 kidneys, 2 ureters, the bladder and the urethra
What are the main processes in the kidney
filtration, reabsorption and secretion
Learn the diagram of the nephron
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What is filtration
water and small molecules pass from the blood into the nephron under high pressure
What is reabsorption
molecules pass from the nephron back into the blood
What is active transport
energy is used to move molecules often against a concentration gradient
What is secretion
some substances pass from the blood into the nephron
Describe the process of filtration
blood enters the nephron and small molecules like glucose amino acids, urea, salts and water are forced into the bowman’s capsule as they are under high pressure from the glomerulus
Describe the process of reabsorption
water useful molecules and salts are reabsorbed in the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule
What does the proximal convoluted tubule reabsorb
most salts, glucose, amino acids and vitamins
What does the loop of Henle (descending limb) reabsorb
some minerals
What does the loop of Henle (ascending limb) reabsorb
some salts
