Structure & Function Of The Brain Flashcards
3 main parts of Brain
Describe
Cerebrum (Cerebal Cortex )- Is the large folded area of the brain . Outer wrinkly bit - and is responsible for conscious thoughts, reasoning, memory and emotions.
Cerebellum -found at the rear of the brain below the cerebrum and controls balance and coordinated movement - muscle coordination
Medulla - found at the top of the spinal cord and contains groups of neurons that transmit electrical impulses to the heart and lungs to control heart rate, breathing rate and peristalsis.
What does a reflex action do
What are 2 types of neuron
What makes reflex actions quick
What is the circuit of the neurons called
A reflex action is a rapid automatic response to a stimulus (anything an organism can detect).
Reflex actions are involuntary and do not necessarily involve the brain.
- Reflex actions protect the body from further damage by allowing it to react quickly to stimuli, such as high temperatures, that may be harmful.
Reflex actions are quick because there is a direct link in the spinal cord called an inter neuron (between the sensory neuron and a motor neuron) that causes a muscle to make the protective response.
The circuit of the neurons that act to produce the reflex action is called the
reflex arc
.
Reflex Arc
- what is the order of Neurons
How do they function
Reflex Arc
- Sensory Neuron > Inter Neuron > Motor Neuron
The neurons are separated by narrow gaps called synapses. When an electrical impulse reaches the end of a neuron chemicals are released from it.
The chemicals diffuse across the synapse and trigger an electrical impulse in the next neuron in the circuit.
Stages of reflex action
Explain in the context of touching a hot plate
Stage 1
- Hand touches hot plate and the high temperature stimulates a pain receptor at the end of a sensory neuron.
Stage 2
- An electrical impulse is transmitted along the sensory neuron.
Stage 3
- The electrical impulse reaches the end of the sensory neuron. Neurotransmitter Chemicals are released that cross the synapse and trigger an electrical impulse that is transmitted along the relay neuron.
Stage 4
- The electrical impulse reaches the end of the relay neuron. Chemicals are released that cross the synapse and trigger an electrical impulse that is transmitted along the motor neuron.
Stage 5
- The electrical impulse is transmitted along the motor neuron. When it reaches the end of the neuron chemicals are released that cross the synapse to the muscle. They cause the muscle to contract (the response) and the hand is pulled away from the hot object.
What are hormones
How are they released into the body and what do they target
Hormones are chemical messengers. Hormones are released from places in the body such as the pituitary gland or pancreas into the bloodstream by groups of cells called endocrine glands.
Hormones are transported in the blood plasma to target body tissues where they bind to cells to produce a response.
A specific hormone can only affect cells if the cells have a receptor for it.
What is important about blood glucose levels
What happens if it’s too low /high
What hormones regulate insulin and glucagon
Where is Glucose kept .
In what form is it stored
The concentration of glucose in the blood must be kept at a set point.
If the blood glucose concentration rises too high then the water concentration of the blood will fall and water will diffuse out of cells by osmosis. This may interfere with cell reactions.
If the blood glucose concentration falls too much, then body cells will not receive as much glucose and so will not be able to release as much energy in respiration.
The concentration of glucose in the blood is regulated by the action of the hormones insulin and glucagon. The target cells of these hormones are found in the liver.
With too much glucose, the pancreas releases insulin to convert the excess glucose into a substance called glycogen which can be stored in fat liver and muscle cells
To little glucose causes the pancreas to secret glucagon, this causes glycogen to turn back into glucose for use in the body
The liver acts as the body’s glucose ‘reservoir’. Liver cells can take in glucose molecules from the blood using insulin and store them in the form of glycogen. Glycogen can be broken down again using glucagon and the glucose released into the blood when it is needed.
What makes up the central Nervous System
Brain
Spinal chord
Made up of billions of interconnected neurons
3 methods to study brain
- Study patients with brain damage
If small part damaged,effective on person can tell you what that part does - Electronically stimulate brain
Using electrodes can stimulate brain by using small zap if electricity. By observation,can get an idea of what that part of brain does - MRI scan
Magnetic resonance imaging {MRI). Provides detailed picture of brain structure. Can use to see what parts are active egblisten to music
