Biology Paper 2 Mock

Maintaining a stable internal environment.
-The regulation inside your body to keep cells in the right positions to function properly, including the right conditions for enzyme action.
-automatic control systems in the body (inc. nervous and hormonal systems) control body temp, blood glucose levels etc.
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Maintaining a stable internal environment.
-The regulation inside your body to keep cells in the right positions to function properly, including the right conditions for enzyme action.
-automatic control systems in the body (inc. nervous and hormonal systems) control body temp, blood glucose levels etc.
What is homeostasis and why is it important?
- Rapid automatic responses to certain stimuli that don't involve the conscious part of the brain (reduce risk of injury)
What are reflexes?
-bright light in eye = pupils get smaller to prevent damage.
-Get a shock= adrenaline released
Examples of reflex actions
The passage of information in a reflex (from receptor to effector)
What is a reflex arc?
central nervous system
Where does the reflex arc go through?
Body temperature is controlled by negative feedback:
1. Temperature receptors detect whether the core body temp is too high/low.
2.Thermoregulatory centre acts as a coordination centre and triggers effectors automatically when info from receptors is received.
3.Effectors produce a response and counteract the change.
How is body temperature monitored/controlled?
Too hot:
-Hairs lie flat
-Sweat produced (and evaporates/transfers energy to environment)
- Blood vessels supplying skin dilate so blood flows closer to skin surface (vasodilation) to transfer energy from skin to environment.

Too cold:
-Hairs stand up (trap air for insulation)
-No sweat produced
-Blood vessels supplying skin capillaries constrict (vasoconstriction)
- Shiver (muscles contract, energy transferred from respiration warms the body)
How do the body's responses act to raise/lower temperature in a given context?
Chemical molecules released directly into the blood and control things in organs/ cells that need constant adjustment.
-Produced by endocrine glands which make up the endocrine system.
-long lasting response
What are hormones?
Pituitary gland:
(behind nose, near underside of brain)
- Hormones produces act on other glands, directing them to produce hormones to bring about change.
Ovaries:
(female reproductive system)
-produce oestrogen for menstrual cycle.

Testes:
(male reproductive system)
-Produce Testosterone to control puberty & sperm production.

Thyroid:
(neck)
-Produces thyroxine to regulate metabolism, heart rate and temperature.

Adrenal Gland:
(on top of kidneys)
-Produces adrenaline for 'fight or flight' response.

Pancreas:
(behind stomach)
-Produces insulin to regulate blood glucose levels.
Locations and functions of the endocrine glands?
-The kidneys make urine by taking waste products out of your blood through filtration. Urea, Ions and Water are removed from the body in urine.
How are water, ions and urea lost from the body?