Homeostasis and Hormones Flashcards
what does our body do to keep warm?
Shivering – uses energy
Releasing energy from food
Vasoconstriction
Hairs stand on end
what does our body do to keep cool?
Sweating which evaporates transferring heat to the environment
Vasodilation
Hairs lie flat
what is homestasis?
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
what happens when RECEPTOR detects a stimulus is too high
EFFECTOR produces a response which counteracts the change and restores the optimum level = level increases
what happens when RECEPTOR detects a stimulus is too low
EFFECTOR produces a response which counteracts the change and restores the optimum level = level decreases
Homeostasis is controlled by…..
Automatic control systems including;
nervous responses
chemical responses.
Homeostasis maintains optimal conditions for ……
Enzyme action and all cell functions
What 4 important things does your body need to keep the same?
Body temperature
30-40 = death
Blood glucose
Water content
Ion levels (salts)
what are some examples of things in your body that need to be kept constant?
One example of the things that needs to be kept constant is the body clock which is normally 37oF. If this goes too high you start to shiver and your hair lies flat. If it goes too low you start to sweat and your hair stands up trapping a layer of conducting air.
Another thing that has to be kept constant is the uear. The kidney produces it and liver removes it from the blood.
Homeostasis
Maintenance of a constant internal environment
Ions
Salts in your body that need to be kept constant
Hypothalamus
The homeostasis control centre of the brain
Thermoregulation
Controlling body temperature
Body temperature
37°C
Diabetes
Disease where the pancreas does not produce enough insulin
Sweating
Method by which heat is taken away from the body via evaporation
Hormone
Chemical messenger used by the organs of the body
How do we get rid of waste? And what would happen if it were to built up?
urine and faeces. chemical reactions and damage cells
What can happen if there is too much or too little water?
damage to cells
What is the sensor in the body that detects heat?
thermoregulatory center in the brain and skin
What is the sensor in the body that detects heat?
Why do we need to keep body temperature the same?
heatstroke, dehydration can occur hypothermia and deatg
What controls the blood glucose levels?
pancreas
Most animals need to find food, avoid danger and find a mate
How is the nervous system vital to all of these?
The nervous system is how animals (including humans) detect changes in the environment around them. Receptor cells detect these changes
Where are most of our receptor cells are located?
They are usually found clustered together in our sense organs, such as the eyes, ears and skin
How the nervous system works
The nervous system carries electrical signals through the body very fast
Stimulus
Receptor
Central nervous system
Effector
hearing a loud noise…..
What is the STIMULUS ?
What are the RECEPTOR/S ?
What is the RESPONSE ?
What is the STIMULUS ? Loud noise
What are the RECEPTOR/S ? Sound Receptors – in the ears
What is the RESPONSE ? Jump / Block ears
where are our receptors found?
Receptors are found in our sense organs
They detect a stimulus
what is the central nervous system made up from?
The central nervous system is made up of the brain and the spinal cord. The Brain is protected by the bone from the skull and the Blood Brain Barrier and the spinal cord is protected by the spinal vertebrae.
what is the function of the peripheral nervous system?
The main function of the PNS is to connect the central nervous system to the limbs and organs.
Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood-brain barrier, leaving it exposed to toxins and mechanical injuries.
nerve
Bundles of neurones.
Neurones
Cells that carry electrical signals from our sense organs to the CNS.
Stimulus
Something that is detected by the receptors in our sense organs.
Central nervous system
Made up of the brain & spinal cord.
Impulses
Electrical signals carried by your nervous system.
Motor neurones
These cells carry information from the CNS to the muscle cells
Sensory neurons
Specialised cells that can carry an electrical signal.
What are the two types of effector?
Effectors =
1.Muscles
2. glands
how do effectors respond?
Muscles respond to the arrival of impulses by contracting
Glands respond by releasing hormones
what is the nervous system pathway?
1) Stimulus
eg: bee on hand
2) Receptor (detects stimulus)
touch/pressure receptor
3) Sensory neurone (travels as an electrical impulse)
4) CNS (brain & spinal cord - coordinator. Decides what action to take)
5) Motor neurone ( travels as an electrical impulse)
6) Effector
eg muscle or gland
7) Response (what the effector does)
eg: arm move
What are we investigating? Reaction time
The aim of the investigation is to measure how a certain factor affects the reaction time.
What could we change during the experiment?
Variables that we can change:
- listening to music vs not listening to music
- listening to pop music vs listening to classical music
- girl vs boy
- older student vs younger student
- exercise vs no exercise
- left hand vs right hand
- caffeine vs no caffeine
Explain why the experiment was carried out 5 times instead of just once?
Ensures the experiment is repeatable, and gives a wide range of data
What is the advantage of calculating an average distance?
It improves the accuracy, and allows you to discount outliers. Gives a value closer to the true value.
How could the experiment be improved to improve the accuracy?
Repeat the experiment more times. Use a computer based test to give a more precise idea of reaction time. (computer can time in milliseconds so results are more accurate. Computer tests are more random so remove the possibility of predicting).
The investigation is looking at the subjects reaction time. State one ethical consideration that must be taken into account in your investigation.
Ensure that the person doing the test has given their permission.
What is different about a reflex reaction?
It is automatic, doesn’t involve conscious thought and is for our own protection
What does a sensory neuron connect?
Receptors and the CNS
What kind of message is sent in a neuron?
Electrical impulse
What is a synapse?
The connection between neurones
What factors which may affect our reaction time?
Caffeine
Medication
Drugs
Alcohol
Age
Level of training/practice
Level of tiredness
Where is the impulse transmitted to? Reflex arc
The spinal cord
What is not involved in the reaction to begin with?
reflec arc
The brain
What is the reaction of the reflex arc?
To retract the part of the body (hand) without input from the brain
why does the reflex arc not include the brain?
To make the reaction faster and so we cannot override the response.
Each reflex action takes the follows the pathway:
stimulus → receptor → sensory neurone → relay neurone (in the spinal cord) → motor neurone → synapses → effector → response