Summary Homeostasis

What is homeostasis

Answer: The redundancy of living organisms to maintain a constant composition of their internal environment, irrespective of changes in the external environment.

Explain how homeostasis is maintained with oxygen and carbon dioxide

Answer: Rate of cellular respiration increases More carbon dioxide releases into blood Medulla oblongata stimulated Impulses sent to heart and breathing muscles Heart beats faster, deoxygenated blood is pumped faster Breathing movements sped up by breathing muscles Carbon dioxide removed faster, oxygen supplied rapidly to tissues Levels are restored

Explain how homeostasis is maintained with osmoregulation if there is too much water

Answer: Large volumes of water in blood stimulate the Osmoreceptors A message is sent to the pituitary gland to secrete less ADH Distal convoluted and collecting tubules become less permeable Therefore less water leaves the tubule which forms dilute urine Less water is reabsorbed into the capillaries Water level decreases back to normal

Explain how homeostasis is maintained with osmoregulation when there is too little water

Answer: Low volumes of water in blood stimulates the osmoreceptors A message is sent to the pituitary gland to secrete less ADH Distal convoluted and collecting tubules become more permeable Therefore more water leaves the tubule which forms concentrated urine More water is reabsorbed into the capillaries Water level increases back to normal

Explain how homeostasis is maintained with salt levels when there is too much sodium

Answer: The adrenal gland secretes more aldosterone more sodium is reabsorbed by the capillaries at distal and collecting tubules less sodium ions are excreted The level of sodium increases back to normal

Explain how homeostasis is maintained with salt levels when there is too little sodium

Answer: The adrenal gland secretes less aldosterone Less sodium is reabsorbed by the capillaries at distal and collecting tubules More sodium ions are excreted The level of sodium decreases back to normal

What layers make up the epidermis

Answer: The epidermis is made out of a horny layer, non-granular layer, granular layer, and germinative layer

What makes up the dermis layer

Answer: blood and lymph vessels, nerve and sense receptors, sebaceous glands, sweat glands and sweat ducts, hair follicles and erector muscles.

How are sense receptors an adaptation of the skin

Answer: Convert stimuli to impulses and transmit these by nerves to the central nervous system. Pacinian corpuscles and corpuscles of Ruffini are sensitive to pressure. Meissner’s corpuscles are sensitive to touch and free nerve endings are sensitive to pain.