TOPIC B5 HOMEOSTASIS AND RESPONSE Flashcards
what is homeostasis
-the regulation of conditions inside your body, to maintain a stable internal environment
-responses to changes in internal and external conditions
state what the automatic control systems are made up of
3main components
1. receptors
2. co-ordination centres
3. effectors
how is the internal environment kept stable
by using mechanisms called negative feedback
-when the levels of somethin
what is the role of a receptor
to detect a stimulus
why does the body need to maintain optimal conditions
for optimal enzyme action and cell function
what’s the difference between internal conditions and external conditions
internal- refers to conditions inside the body e.g body temp
external- refers to conditions outside the body e.g room temp
what is the role of a coordination centre
receives and processes the information from receptors then organises a response
what is the role of an effector
to produce a response
what are the 2types of effectors and what do they do when stimulated
muscles- contract
glands- release hormones
what is negative feedback
a mechanism that restores a level back to optimum in a system
Name 2 internal conditions
-blood glucose concentration
-blood pH
Name 2 external conditions
-room temp
-amount of fluid you drink
Homeostasis relies on automatic control systems.
In what order are signals passed along the control system?
receptor➔ coordination centre ➔ effector
where are the coordination centres located in the body
-spinal cord
-brain
what passes along nerve cells
electrical impulses
homeostatis relies on …..
negative feedback
for when the levels of something get too high theyre brought back down, and when something get too low theyre brought back up
If our body temperature gets too high, negative feedback will cause our temperature to
decrease back down
what is the purpose of the nervous system
to detect changes in the environment (stimuli) and to coordinate responses
Name 4 different parts of a nervous system
-Central Nervous System
-Sensory neurones
-motor neurones
-effectors
what is the Central Nervous System composed of
-brain
-spinal cord
connected to the body by sensory and motor neurones
what is the gap between two neurone called
synapse
whats released across a synapse
chemicals
what is the sensory neurone
-the neurones that carry information as electrical impulses from the receptors to the CNS
whats a motor neurone
-neurones that carry electrical impulses from the CNS to effectors
what are 2 receptors
-taste on the tongue
-sound in the ears
what does the central nervous system do
it receives infomation from the receptors and then coordinates a response
What does Homeostasis control?
-Blood glucose concentration
-body temperature
-water levels.
reflex actions control what
everyday bodily functions
e.g breathing and digestion
state the reflex pathway
stimulus—- receptor—– sensory neurone—– relay neurone—- motor neurone—- effector—- response
What are reflexes?
Automatic and rapid reactions which don’t involve conscious parts of the brain. Involve sensory, relay and motor neurones. Control breathing, digestion, avoiding danger
What is the endocrine system?
Glands that secrete chemicals called hormones directly into the bloodstream. Blood carries the hormone to a target organ where it produces an effect. Slower but longer lasting
]What is the pituitary gland?
Master gland which secretes several hormones into the blood.
Name the key Endocrine glands
Pituitary,
-Thyroid,
-Pancreas,
-Adrenal,
-Ovaries
-Testes
What is the pituitary gland?
Master gland which secretes several hormones into the blood.
Blood glucose concentration?
Pancreas produces insulin which allows glucose to move from the blood into the cells and to be stored as glycogen in the liver and muscles.
-Also produces glucagon which allows glycogen to be converted back into glucose and released back into blood. Negative Feedback Cycle
compare type 1 diabetes to type 2
-in 1, the blood glucose rises to fatally high levels as the pancreas doesn’t have secrete enough insulin
-in 2, the body stops responding to its own insulin
how is type 1 diabetes controlled
insulin injections to replace hormone not made.
How can Type 2 diabetes be controlled?
Carbohydrate controlled diet, more exercise. Drugs may be needed
What does Thyroxine do?
Stimulates basic metabolic rate. Growth and development
state the 4 stages of the menstrual cycle
- day 1- menustration starts and the uterus lining breaks down for 4days
- uterus line builds up again
- an egg develops and is released from the ovary, which is ovulation
- wall is maintained
state the 4 horomes
- FSH (follicle-stimulating hormone)
- Oestragen
- LH (lutenising hormone)
- progesterone
what is FSH
produced in the pituitary gland, causes an egg to mature and stimulates the ovaries
what is oestrogen
-produced in ovaries
-causes lining of uterus to grow
-stimulates the release of LH and inhibitis release of FSH
what is LH
-produced by pituitary glands
-stimulates release of an egg
what is proggesterone
-produced in ovaries
-maintains the lining of the uterus during 2nd half of the cyle
-inhibits the release of LH and FSH
how does oestrogen be used to reduce fertility
-can be used to prevent the release of an egg, method of contraception
how does progesterone reduce fertility
-stimulating the production of thick mucus which prevents sperm getting through
state 3 ways to avoid pregnancy
- sterilisation, cutting the fallopian tuves in a female
- natural methods, finding out when the womens most fertile and avoiding sex on them days
- abstinence, to not have intercourse
pros and cons of the fertility drug
PROS
-helps women get pregnant
CONS
-doesn’t always work, and then could be expensive to keep buying
-too many eggs can be stimulated, means unexpected multiple pregnancies
how does IVF help couples to have children
-collects eggs from womens ovaries and fertilises them in a lab, using mans sperm
-fertilised eggs are grown into embryos
