Biology 20 questions (homeostasis)

Homeostasis

maintaining a stable internal condition for optimum enzyme/cell activity

Stimulus

a detectable change in the physical or chemical structure of an organisms internal or external environmentw

what detects a stimulus

a receptor

example of ‘effector’

a muscle (movement) or a gland (hormone release

nervous pathway for a reflex action

stimulus - receptor- sensory neurone- relay Neurone- motor Neurone- effector- response

difference between a voluntary response and a reflex arc

a voluntary response takes longer

voluntary is co-ordinated in the brain

reflex is not co-ordinated in brain so is much faster

synapse

the connection and gap between neurones

Difference between nervous and endocrine systems

nervous- releases nerve impulse as messages. Fast, short live, specific

endocrine-releases chemical messages (hormones). slow, long lasting, may affect one or many parts of the body (non specific

what hormone lowers blood glucose levels

insulin

where is insulin hormone produced

the pancreas

which hormone raises blood glucose levels and where is it produced

glucagon and in the pancreas

type 1 diabetes

no insulin is produce, often detected early on in life

type 2 diabetes

insulin may still be produced, but poor lifestyle, such as obesity, causes cell receptors to no longer respond to insulin

function of FSH

-matures the egg

-stimulates oestrogen production

function of oestrogen

-thickens lining of uterus

-stops FSH

-stimulates LH release

LH

-releases egg

role of TSH and Thyroxine

TSH(produced in pituitary gland) stimulates thyroxine.

thyroxine (produced in thyroid gland) stops TSH

they are a negative feedback relationship

what term describes the control system where the detection of a high level of a chemical causes a reduction in the production of that chemical

negative feedback

what hormones are in the contraceptive pill and why

•  High levels of oestrogen inhibit FSH production preventing the maturation and release of eggs

• Progesterone also plays a role in inhibiting LH so the release of mature eggs and stimulates the production of a thick mucus which prevents sperm from reaching any eggs that are released

which hormones are involved in IVF treatment?

LH and FSH