Nerves and Homoeostasis Flashcards
What are the 5 sense organs?
Tongue, Nose, Ears, Eyes, Skin
What is a stimulus?
A change in environment
What is a receptor?
Something sensitive to a stimuli
How do receptors work?
They change stimulus energy into electrical impulses
Name examples of stimuli
Light, Sound, Touch, Pressure, Pain, Chemical
What receptors are in your eyes and what do they contain?
Light receptors - Have nucleus, Cytoplasm, Cell membrane
What receptors are in your ears and what do they contain?
Sound and balance receptors - Sensitive to change in position
What receptors are in your nose and what do they contain?
Smell receptors - Sensitive to chemical stimuli
What receptors are in your tongue and what do they contain?
Taste receptors - Sensitive to bitter, salt, sweet tastes (chemical stimuli)
What receptors are in your skin and what do they contain?
Sensitive to touch, pressure and temperature change
What are sensory neurons?
Nerve cells which carry electrical impulses from receptors to organs in the CNS
What are relay neurons?
Nerve cells which carry signals from the sensory neurons to the motor neurons
What are motor neurons?
Nerve cells which carry signals from the CNS to effector muscles or glands
What does the CNS consist of?
Spine and brain
What happens at the CNS?
Coordination centres - Where information from the receptors in sense organs is sent to and where responses are coordinated e.g to effector muslces
What do control systems consist of?
Receptors -> coordination centres -> effectors
What is the role of a control system in your body?
To keep conditions constant by responding to stimuli
What is the connection between 2 neurons called?
Synapse
How is the nerve signal transferred across a synapse?
By the chemicals which diffuse across the gap
What happens next after the chemicals have diffused across a synapse?
The chemicals set off a new electrical signal in the next neurons
What is a reflex?
A response to a stimuli
What is the passage of information in a reflex called?
A reflex arc
Where does a reflex arc go through in your body?
CNS
What is the brain responsible for in terms of behaviour?
Complex behaviours
What is the function of the cerebral cortex in your brain?
Consciousness, memory, language and intelligence (-> If you’re reading this, you need more)
What is the function of the medulla in your brain?
Controls unconscious activities e.g heart rate and breathing
What is the function of the cerebellum in your brain?
Muscle coordination
What is the function of your spinal cord (top end which connects to your brain)?
Part of the CNS
What are methods to see which part of the brain has been damaged?
Ask patient what effect he is having e.g blind
MRI scans
Electrically stimulating the brain
What needs to be kept constant in your body?
Water levels, glucose levels, temperature, ion content
What is the system called which keeps levels constant in your body?
Automatic control systems
What is a hormone?
Chemical substances secreted by glands
Where do hormones travel?
In the bloodstream to other parts in the body, but only effect particular cells
What is responsible to keep your ion content constant?
Kidneys
What happens if you eat a food with too much of an ion?
You shit, or piss it out
Where is water lost in your body?
Skin with sweat
Lungs with respiration
Kidneys with urine
What controls your water levels in your body?
Hormones
What is the optimum temperature for most of the enzymes in your body?
37C
What temperature does your body try to maintain at?
37C
Which part of your body controls body temperature?
Brain
What 2 hormones allow you to maintain a constant level of glucose in your blood?
Glucagon and insulin
What part of your body controls your blood sugar levels?
Pancreas
What is the job of the liver?
Deamination and detoxification
What does the liver break down amino acids into?
Ammonia
Why does your liver need to break down amino acids?
Because too many are harmful if they stay in your body
What does ammonia get converted into?
Urea
Where is urea lost in your body?
Sweat and urine
Name some substances that your liver breaks down
Alcohol, drugs and unwanted hormones
What is the process called where the liver breaks down alcohol?
Detoxification
Where are substances which have been detoxificated go?
In your urine
What does your body do with old blood cells and why?
Breaks them down and stores them because they have iron in them
What is the main function of your kidneys?
Filtering your blood to produce urine
What happens to stuff that isn’t filtered by your kidneys?
It is reabsorbed
Name some products which could be reabsorbed
Glucose, water, dissolved ions
What is ultrafiltration?
A high pressure which squeezes mater, urea and ions and sugar out of the blood (and into bowman’s capsule)
(Basically what goes on in the filtering of the blood)
What stops bigger molecules like RBCs being filtered into your urine?
Membranes between blood vessels in the Bowman’s capsule
What goes on in the reabsorption
As the liquid flows through the nephron, useful substances are reabsorbed
Which type of movement of ions is involved with the reabsorption of glucose?
Active transport
Which part of your body keeps water levels constant?
Kidneys
Why do you want to keep your water levels constant?
Controls rate of osmosis and blood pressure
What hormone controls how much water is absorbed?
ADH
How does ADH allow more water to be absorbed?
Makes nephrons more permeable
What gland releases ADH?
Pituitary gland
Where is the pituitary gland located?
In the brain
What happens if more ADH is released?
The kidneys reabsorb more water and more concentrated urine is produced
What happens if less ADH is released?
The kidneys reabsorb less water and less concentrated urine is produced
What type of urine do you have if you drink lots of water?
Dilute urine
What type of urine do you have if you don’t drink lots of water?
Concentrated urine
What can trigger ADH to be released?
Exercise, lack of water and heat
What happens in the blood if kidneys don’t work properly?
Waste substances build up and you lose the ability to control levels of ions and water
What is are treatments for kidney failure?
Dialysis or kidney transplant
What happens in dialysis
The persons blood flows between partially permeable membranes surrounded by dialysis fluid
What concentration of glucose is in dialysis fluid and why?
The same as human concentration levels so glucose isn’t lost in the fluid
What diffuses into the dialysis fluid from human blood?
Waste products and excess ions and water
What are risks of dialysis?
Can cause blood clots and infections
What is an advantage of dialysis?
Keeps patient alive
What are some disadvantages of dialysis?
Takes around 12-16 hours per week
Expensive
Risk of blood clots and infections
Need pills to thin blood
What is the only cure for a kidney failure?
Transplant
What happens to your skin when you’re too hot?
Hairs lie flat, sweat produced, vasodilation
What happens to your body when you’re too cold?
Hairs stand up, no sweat, vasoconstriction, shiver
What happens in vasodilation?
Blood vessels dilate so more blood flows closer to the surface of the skin and have a larger SA
What happens in vasoconstriction?
Blood vessels constrict so less blood flows closer to the surface of the skin and have a smaller SA
When is insulin secreted into the bloodstream?
When the levels of glucose are too high
What does insulin make the liver do?
Turn glucose into glycogen and store it
What does glucagon make the liver do?
Turn glycogen into glucose and secrete it into the bloodstream
What can someone with type 1 diabetes not do?
Produce insulin
What precautions does someone with diabetes need to take?
Careful diet,exercise regularly and inject insulin into them
What happens to the insulin someone with type 2 diabetes produces?
It isn’t effective because their body is resistant to it
What can increase your risk of type 2 diabetes?
Bad diet and being a fat shit
