2.77b - thermoregulation

- a negative feedback loop is the control of our conditions
- for humans, to regulate a temperature of 37/38 degrees celesis the reactor is the hypothalamus in the brain
- if the temp has increased of decreased then the effector would be the skin
- the response would be the increase or decrease of body temp - then it would feedback to the brain
- the control of body temp by the skin would be the sweat glands
- depending on the temp the blood would move closer (hot day) or further away (cold day) from the skin
- sweating on a hot day and hairs are flat
- shivering on a cold day and hairs are raised

2.77a - thermoregulation

- homostatis is the maintenance of a constant internal environment, like a fixed pH
- homeothermic is maintaining the same temp and body water content
- when the temperature of the environment changes then the body temp stays the same
- this is the same idea with the fixed pH

2.76 sensitivity

- sensitivity is how organisms respond to changes in their environment
- these changes may be light, temperature, pressure or chemical
- the receptor identifies the change and the effector responds to the change - an effector may be muscles
- the response is making sure the organism adapts to its new environment

2.75 - urine

- urine contains water, urea and salts
- salt , water and urea amount vary with how well a person is operating

2.74 - ADH

- ADH - anti- divretic hormone
- it is produced in the brain in the hypothadumus
- ADH goes through the blood from the brain and its target is the kidney
- the effect is to control and alter the quanity of the deposition of water in the blood
- this makes the blood more or less concentrated
- ADH targets the collecting duct
- this allows more water to come out of the collecting duct
- this makes the collecting duct more porous
- the urine would be more concentrated and the volume decreases

2.73 - glucose re-absoption

- glucose goes from the glomerula filtrate to the blood
- urine does not contain glucose
- in the proximal convaluted tubule glucose is removed and is taken back to the blood

2.72 - water re-absorption

- when the filtration occurs in the bowman's capsule, it will filter out too much water
- when it reaches the collecting duct, water is removed form the collecting duct
- the water is then returned to the blood
- this is selected re-absoption of water