Summary Combined biology paper 2

BIO PAPER 2
BIO5
Homeostasis= maintenance of a constant internal environment
-​ Blood glucose concentration
HIGH
-​ Levels rise after eating, which is recognised by the pancreas
-​ Pancreas produces insulin
-​ Insulin causes cells to remove glucose from blood
-​ Liver and muscle cells convert glucose into glycogen, which is stored in liver
-​ Blood glucose levels fall
LOW
-​ Pancreas produces glucagon
-​ Glycogen in liver is broken down into glucose and returns to the blood
-​ Levels rise
-​ Water levels
-​ Temperature

Brain= control centre ---> CNS= sending signals to body (brain and spinal cord)
Pancreas= produces insulin
Effectors/ muscles= moving e.g. shivering
Glands= hormones

Reflex= unconscious (does not involve brain)

Nerve cells are long so it can send a fast electrical signal ---> signal slows when crossing
synapse.
-​ Slow chemical signal
Pituitary gland= in head ---> FSH and LH
Thyroid= in neck ---> regulates metabolism
Adrenal glands= in kidney ---> flight or fight response
Pancreas= behind stomach ---> insulin to regulate blood glucose levels
Testes= testosterone ---> growing hormone in men
Ovaries= Oestrogen ---> maturation of eggs

Type 1 diabetes
-​ When pancreas doesn’t produces right amount of insulin
-​ Weight loss, increased need to wee, thirst, blurry vision, sleepy, hunger
-​ Insulin injections
Type 2 diabetes
-​ Cells become insensitive to insulin
-​ Weight loss, increased need to wee, thirst, blurry vision, sleepy, hunger
-​ Controlling diet
-​ Exercise

FSH= makes egg grow to be released from ovaries
LH= releases egg
Oestrogen= increases till it stimulates LH
Progesterone= increases slowing and builds up uterus lining