Homeostasis Flashcards
Define homeostasis
The regulation of internal conditions in the body to maintain optimum conditions for function, in response to external/internal changes.
What does homeostasis control?
Glucose levels in the blood
Water levels
Temperature
they are maintained but fluctuate
Explain the structures in the reflex arc.
Receptor cells – Sensory neuron – relay neuron (in CNS) – motor neuron– effectors
What is the nervous system?
What is the endocrine system?
A system of nerves, sending electrical impulses to send signals
A system of glands, secreting hormones into the bloodstream to send signals
What is a hormone
A chemical secreted from glands into the blood stream to send signals.
What is the CNS responsible for?
The brain and spinal cord interpret changes and decide the response
Why is the reflex arc important?
They complete actions unconsciously so they are rapid, this protects us
What is the function of synapses in the reflex arc?
Gaps between neurones, electrical impulse arrives at end of the presynaptic neurone, neurotransmitters (chemicals) are released, diffuse across synapse, bind with receptors on postsynaptic neurone, triggering an impulse.
Describe the reaction time practical.
Person 1 holds 1m ruler against table vertically at 0cm and person 2 stand against it.
Person 1 drops the ruler randomly for P2 to catch.
Do this multiple times then swap. Convert the distances into reaction times.
Describe the parts of the nerve cell+ functions.
Dendrites- receives signals
Nucleus- Controls
Myelin sheath- Insulates electrical impulses
Axon- Transfers signals
Synapse- Convert electrical impulses into chemical
Explain how the endocrine system works
Glands secrete hormones into the bloodstream, which comes into contact with cells, some of these cells have receptors specific to the hormone to send signals.
Name the glands.
Pituitary
Thyroid
Adrenal
pancreas
ovaries/testicles
Name the hormones produced by glands
TSH (detects low thyroxine)
Thyroxine (metabolism)
Adrenaline (flight/flight in times of stress or fear)
Insulin (brings down glucose levels)
Puberty + sperm production/ menstrual cycle
Explain the differences between the endocrine and nervous system
Endocrine:
Produced by glands
Hormones in bloodstream
Lasts longer, but slower
More generalized
Nervous:
Electrical impulses by nerve cells
faster, precise
Explain what adrenaline does.
In times of fear or stress, adrenaline increases our heart rate meaninig faster delivery of oxygen and glucose to brain, needed for respiration (exo). And makes us sweat/shiver.
Describe the process of reducing blood sugar levels when they’re too high.
When we consume carbs, they’re absorbed into the bloodstream. Causing blood sugar levels to rise, so our pancreas produces insulin, which is detected by specific receptors to allow the carbs to be absorbed.
Describe the process of increasing blood sugar levels when they’re too low.
Excess glucose is stored in muscles and the liver as glycogen, whenever there isn’t enough glucose in the bloodstream, glucagon is produced by the pancreas to breakdown glycogen into glucose.
Explain how blood sugar levels are decreased when they are too high?
The pancreas detects the high levels and releases insulin which passes through the bloodstream and binds to cells. some will have specific receptors to allow insulin to enter the cell (muscle/liver cells) to absorb the glucose to form glycogen.
What does diabetes mean?
When a person can’t regulate blood glucose levels.
Explain the difference between type 1 and 2 diabetes.
Type 1: Happens in childhood, pancreas stops producing insulin.
Type 2: Elderly, body resistant to insulin, cells don’t take in glucose.
How do you treat type 1 and 2 diabetes?
Type 1: take insulin injections after food
Type 2: Older people with bad diets get it, so low sugar diet + exercise.
What is puberty?
Period in which adolescents develop secondary sexual characteristics.
What hormones are most important in puberty.
Testosterone and oestrogen.
Describe the parts in the female reproductive system.
Uterus, ovaries, fallopian tubes and uterus lining.
