B10 - the human nervous system Flashcards
What is homeostatis?
The maintenance of constant internal body conditions.
Why is homeostatis important for the body?
- Enzyme activity as enzymes need to operate at certain pH and temperatures to make sure reactions happen efficiently
- Cell Size as changes in the water potential in blood will affect the amount of water in the cells. This can cause animal cells to shrivel or swell and burst.
-Independence from external conditions with constant internal environment can maintain a constant level of activity regardless of their environment.
Give some examples of conditions and body that is controlled by nervous or chemical responses.
Water and ions, temperature, blood sugar
Describe the process of you detecting a stimulus and then you reacting to it.
Specialised cells called receptors detect a change and then send an electrical impulse to a sensory neuron. The electrical impulses travel along the nerves the central nervous system - brain and spinal cord. The CNS makes sense of the electrical impulses. It receives and sends new impulses out to the rest of the body along motor neurones. The neurones carry the organs called effectors.
Name me three sensory organs and the receptors in them.
Eye - light, moisture
Ear - sound, balance
Tongue - chemical
Skin - temp, pressure, touch
Nose - chemical
Describe the function of the nervous system in humans?
The nervous system allows all parts of our body to communicate with each other.
Describe how information is passed through the nervous system?
Receptors detect something, sensory neurone is sent out, CNS detects this and sends out a motor neurone, your body reacts to this by using a muscle or gland.
Explain how the structure of the nervous system is adapted to its functions
Neurones with long axons - to allow long distance transmition.
Reflex arcs - which provide quick automatic responses to stimuli bypassing the brain to protect the body from harm.
Synaptic connections- allow for precise communication between neurons and target cells.
Explain the importance of reflex actions
They are crucial for survival as they allow the body to respond quickly by often bypassing the brain to minimise reaction time. This rapid involuntary response helps protect the body from injury, such as pulling your hand away from a hot surface before feeding pain.
Explain how the structures in a reflex arc relate to their functions
Receptors - detect stimulus and generate nerve impulse in response.
Sensory neurone - carries the impulse from the receptor to the spinal cord or Brainstem.
Relay neuron - located in the spinal cord it processes the signal and connect the sensory neuron and motor neuron.
Motor neuron - send the impulse from the spinal cord to the muscle or gland.
Effector - execute the response such as contracting a muscle to move away from harm harm.
Describe a method to investigate the effect of a factor on human reaction time?
One person sits down with their arm resting on the table, putting their hand at the edge of the table with their thumb and finger about 2 cm apart, ready to catch the ruler.
* -The second person holds the ruler above them, with the 0 cm mark level with the top of the their finger.
* -Without warning, the partner drops the rule and they then try to catch it as quickly as possible between their thumb and finger.
* -Record the point on the ruler where the subject catches it.
* -Repeat the test 5 times, and calculate the average reaction distance.
Give 3 examples of reflexes and their importance to the body.
Knee jerk - prevents muscle from overstretching
Blinking - stops eye drying out and stuff getting in them
Pupils response to light - protects eyes from extensive light.
Describe the role of the brain
Describe where you would find the cerebral cortex, cerebellum and medulla in a brain diagram
Cerebral cortex - the main squishy bit
Cerebellum- the star thing at the back
Medulla - tube that comes out the bottom.
Describe the functions of the cerebral cortex, cerebellum and medulla.
Cerebral cortex - consciousness , memory, intelligence and language.
Cerebellum- muscle coordination
Medulla - unconscious activities (breathing , heart rate)
