B5 Flashcards
Define homeostasis
Maintenance of a constant internal environment
Name 3 things that are controlled by homeostasis
Body temperature
Blood glucose
H20 and C02 levels
Name the 2 types of response processes controlled by homeostasis
Nervous or chemical repsonse
What are receptors?
Detect stimuli
What do coordination centers do?
Receive and process information from receptors
What are effectors?
Muscles or glands which initiate the response
What does the nervous system do?
Enables humans to react to their surroundings and to coordinate their behaviour
Name the 2 parts of the CNS
Brain
Spinal cord
How does information from receptors pass along neurons to the CNS?
As electrical impulses
What does the CNS do?
Coordinates the response of the effectors?
What do the effectors do when coordinated?
Muscles contract
OR
Glands secrete hormones
What is the main job of a receptor?
Coordinate effector response
What are reflex actions?
Actions that do not involve the conscious part of the brain
Name the nervous pathway
(Stimulus)
Receptor
Sensory neuron
CNS
Motor neuron
Effector
(Response)
How long does the average menstrual cycle last?
28 days
Describe the first stage of the menstrual cycle and how many days it lasts.
Menstruation = day 1 - 5
Period of bleeding when the uterus lining breaks down
Describe the second stage of the menstrual cycle and how many days it lasts.
Pre-ovulation = day 5 - 14
Egg matures and the uterus lining builds up
Describe the third stage of the menstrual cycle and how many days it lasts.
Ovulation = day 14 - 21
Release of an egg form the ovary
Describe the fourth stage of the menstrual cycle and how many days it lasts.
Pre - menstruation = day 21 - 28
Maintenance of the uterus lining
What happens if there is no fertilised egg after stage 4?
The cycle repeats
What happens if there is a fertilised egg implanted in the uterus after stage 4?
The menstrual cycle stops and the lining is maintained (due to progesterone)
Name the four hormones involved in the menstrual cycle
FSH
LH
Oestrogen
Progesterone
What is the role of FSH?
Matures an egg
Stimulates oestrogen production
What is the role of oestrogen?
Builds up uterus lining
What is the role of LH?
Release of an egg = OVULATION
What is the role of progesterone?
Maintains uterus lining
Detects the release of an egg (this then means the lining is broken down
What is the role of testosterone?
Stimulates sperm production
Male sexual characteristics
Where is testosterone maintained?
Testes
Where is FSH and LH produced?
In the pituitary gland
Where is oestrogen and progesterone produced?
In the ovaries
Describe the endocrine system.
A system (a network of glands and organs) that produce hormones and transport them through the bloodstream. The endocrine system is a slow procedure that is a long duration
What is the role of adrenaline?
Prepares the body for fight or flight
Transfers glycogen to glucose for energy
Describe 3 changes that occur due to a release of adrenaline
Increased HR
Increased BR
Increased BP
Where is adrenaline produced?
Adrenal glands
What is the role of thryoxine?
Controls metabolic rate
Controls how fast substances in the body are broken down or built up
Where is thyroxine produced?
Thyroid glands
What is negative feedback?
Negative feedback maintains levels in the body meaning they’re not too high or too low.
COUNTERACTS
What is the negative feedback with TSH and THYROXINE?
If TSH increases, THYROXINE will decrease
Does thyroxine inhibit or stimulate TSH production?
Inhibits
Does TSH inhibit or stimulate thyroxine production?
Stimulate
