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To regulate temperature, what does the skin do in cold conditions? (3)
- Hairs stand up to keep skin warm (piloerection).
- Blood vessels become narrow (constrict) to retain heat (vasoconstriction).
- Shivering (increases metabolism).
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To regulate temperature, what does the skin do in warm conditions? (2)
- Sweating- cools the body due to evaporation
- Blood vessels widen (dilate) to lose heat
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What are the 4 functions of the skin?
- Protection
- Vitamin production
- Store food
- Sense
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How does the skin perform protection? (3)
- Epidermis protects against damage, water loss and the entry of pathogens
- Melanin protects against ultraviolet radiation
- Sebum (oil) keeps the epidermis intact
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What vitamin is made in skin?
Vitamin D
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What stores energy in the skin?
Fat stores energy in adipose tissue.
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What are 3 things skin can sense?
A sense organ- sensing touch, pain, temperature.
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What are the 3 main excretory organs?
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What do each of the 3 main excretory organs excrete?
- Lungs - water + carbon dioxide
- Skin - water + salts
- Kidneys - water + salts + urea
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What does the urinary system consist of? (4 body parts)
- 2 kidneys
- 2 ureters
- Bladder
- Urethra
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What are the 4 sections of the kidney?
- Cortex- Outer darker region
- Medulla- Inner lighter region
- Pelvis
- Ureter- Brings urine to bladder
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What is urea?
Excess amino acids broken down
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Give description of how kidneys make urine? (4 points)
- Blood enters through renal arteries
- Filtration- kidneys filter waste and useful materials (occurs in cortex) eg. of wastes- urea, excess salts. eg. of useful materials- glucose, water
- Reabsorbtion- useful materials are reabsorbed back into blood (occurs in cortex and medulla)
- Secretion- wastes- urea, some salts, water etc. are secreted from the blood
- Urine is formed and flows to bladder through ureters
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What artery does blood enter the kidneys through?
Renal arteries
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Blood entering the kidneys are rich in what?
Blood entering the kidneys are rich in wastes.
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What is filtered by the kidneys from the blood?
Wastes but also useful materials
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What are reabsorbed from the kidneys back into the blood?
Useful materials are reabsorbed from the kidneys back into the blood (ie. food and water- glucose, amino acids, some salts).
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Where is urine formed?
Urine is formed in the kidneys.
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What does urine flow through to reach the bladder?
Urine flows through ureters to the bladder.
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Where does the ureters carry urine to?
The bladder.
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In the renal veins, what is blood low in?
Blood is low in waste in renal veins (leaving kidneys).
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