maintaining constant conditions in the body. Maintaining a constant internal environment
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What do Kidneys do
They filter the blood, remove unwanted substances and control the concentration of water and solutes
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What are the two main functions of kidneys
Controls the water and salt ion concentration in the blood. Filters urea in the blood.
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Explain the formation of Urea (1)
Proteins are broken down by protease enzymes into amino acids. Excess AA are transported to the liver from the small intestine and can't be stored
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Explain the formation of Urea (2)
Liver converts AA to ammonia. Ammonia is converted to urea. Urea released by the liver and taken into the bloodstream where it's filtered out by the kidneys and passes into urine.
High pressure from the glomerulus by the diameter of the capillary leaving the glomerulus being narrower than the capillary entering
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What does the pressure do
Results in ultrafiltration where water, salts, glucose, and other small molecules pass out of the capillary and into the Bowman's capsule
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Last notes on Bowman's capsule
Fluid that enters the Borman's capsule is called glomerular filtrate. Proteins and blood cells are too big to leave the capillaries to go into the tubule
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What is reabsorption
Glucose is reabsorbed in proximal tube. Water is reabsorbed in the loop of henle. and salt and urea passes through to urine.
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How is the body's water content controlled
The pituitary gland produces ADH (Anti-Diuretic Hormone)
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What happens when there is too little water in blood
Hypothalamus detects it. PG releases ADH. More water is reabsorbed by kidneys, collecting ducts are more permeable. Less water is lost in urine. Blood water level returns normal.
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What happens when there is too much water in blood
Hypothalamus detects it. PG releases less ADH. Less water reabsorbed by kidneys. More water lost in urine. Back to normal.
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What is an Endotherm and Ectotherm
An animal that is able to mantain internal body temperature (warm-blooded). Animal that is dependent on the surround environment to maintain body temp (cold blooded)
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Why is skin important
Tough outer layer resist mechanical damage. Prevent entry of pathogens. Prevents water loss. Sense organ. Controlling heat loss.
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What is the epidermis
Outere layer of skin that protects us against harmful microorganisms entering the body
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What is the dermis
Middle layer of skin that consists of blood capillaries, nerve endings, sweat glands and hair follicles
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What is the hypodermis
The inner layer that containst fatty tissue for insulation
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How do sweat glands maintain body temp
As sweat spread through the surface of the skin evaporates, it uses thermal energy from the skin to turn water molecules into vapour. Leaves the skin cooler.
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How does hair maintain body temp
When cold, the CNS causes the hair erector muscle to contract and pull the hair to a more vertical position in the follicle. Layer of air trapped between them and the body is better insulated
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What is vasodilation
Hot conditions. Blood vessels close to the surface of the skin widen and allows more blood to flow near the surface so more heat is lost by radiation
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What is vasoconstriction
Cold conditions. Blood vessels near the surface constrict and less blood flows. Less energy is transferred to the surroundings.
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Other cards in this set
Card 2
Front
What do Kidneys do
Back
They filter the blood, remove unwanted substances and control the concentration of water and solutes
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