Nervous System / Neurons / Synaptic Transmission (Biopsychology)

Question 1

What does the nervous system do?

Answer 1

• Your nervous system allows you to respond to changes in your environment and coordinate your actions.
• Receptors detect stimuli and effectors bring about a response to this. (effectors = muscle cells and glands)
  The nervous system has two key parts:
  –> The central nervous system
  –> The peripheral nervous system

Question 2

What is the central nervous system?

Answer 2

• This includes the brain and the spinal cord and has two main functions: the control of behaviour and the regulation of the body’s
  physiological processes.
• In order to do this, the brain must be able to receive information from the sensory receptors (eyes, ears, skin, etc.) and be able to send messages to the muscles and glands of the body.

Question 3

What is the role of the spinal cord in the central nervous system?

Answer 3

• The main function of the spinal cord is to relay information between the brain and the rest of the body.
• This allows the brain to monitor and regulate bodily processes, such as digestion and breathing, and to coordinate voluntary movements.
• The spinal cord is connected to different parts of the body by pairs of spinal nerves, which connect with specific muscles and glands.
• The spinal cord also contains circuits of nerve cells (relay neurons) that enable us to perform some simple reflexes without the direct
  involvement of the brain.

Question 4

What four main areas can the brain be divided into?

Answer 4

• The brain can be divided into four main areas – the cerebrum,
  cerebellum, diencephalon and brain stem.

Question 5

What is the cerebrum?

Answer 5

• The cerebrum is the largest part of the brain, and is further divided into four different lobes, which each have different functions.

Question 6

What is the cerebellum?

Answer 6

• The cerebellum is involved in controlling a person’s motor skills and balance, coordinating the muscles to allow precise movements.

Question 7

What is the diencephalon?

Answer 7

• The diencephalon has two important structures, the thalamus and the hypothalamus.
• The thalamus acts as a relay station for nerve impulses coming from the senses.
• The hypothalamus has a number of important functions, including the regulation of body temperature, hunger and thirst. It also controls the release of hormones from the pituitary gland.

Question 8

What is the brain stem?

Answer 8

• The brain stem is responsible for regulating the automatic functions that are essential for life.
  –> These include breathing, heartbeat and swallowing.
• Motor and sensory neurons travel through the brain stem, allowing impulses to pass between the brain and the spinal cord.

Question 9

What is the peripheral nervous system?

Answer 9

• All the nerves outside the CNS make up the peripheral nervous system.
• The function of the PNS is to relay nerve impulses from the CNS (the brain and spinal cord) to the rest of the body and from the body back to the CNS.
  There are two main divisions of the peripheral
  nervous system:
  
  1. The somatic nervous system
  2. The autonomic nervous system (ANS).

Question 10

What is the somatic nervous system?

Answer 10

• The somatic system is made up of 12 pairs of cranial nerves
  (nerves that emerge directly from the underside of the brain) and 31 pairs of spinal nerves (nerves that emerge from the spinal cord).
• These nerves have both sensory neurons and motor neurons.
• The somatic system is also involved in reflex actions without
  the involvement of the CNS, which allows the reflex to occur
  very quickly.

Question 11

What is the autonomic nervous system?

Answer 11

• Involuntary actions such as breathing and your heart beating are regulated by the ANS.
• The ANS has two parts: the sympathetic and the parasympathetic.
• The sympathetic division uses the neurotransmitter noradrenaline, which has stimulating effects (speeds things up – fight or flight), and the parasympathetic division uses acetylcholine, which has inhibiting effects (slows things down).

Question 12

What are the effects when there is a sympathetic nervous system activation?

Answer 12

Sympathetic response: The sympathetic nervous system is activated, initiating the “fight or flight” response.
- Heart Rate Increases: To pump more blood to muscles.
- Breathing Rate Increases: To increase oxygen intake.
- Release of Adrenaline: Adrenal glands secrete adrenaline (epinephrine) and noradrenaline (norepinephrine), further preparing the body for action.
- Pupil Dilation: Enhances vision to better assess the situation.
- Digestion Slows Down: Blood flow is redirected from the digestive system to muscles.

Question 13

What are the effects when there is a parasympathetic nervous system activation?

Answer 13

Parasympathetic Response: The parasympathetic nervous system activates, initiating the “rest and digest” response.
- Heart Rate Decreases: Returns to a normal, resting rate.
- Breathing Rate Decreases: Returns to a calm, steady pace.
- Digestion Resumes: Blood flow returns to the digestive organs, promoting digestion.
- Muscle Relaxation: Muscles that were tense during the chase start to relax.
- Sense of Calm: Overall feeling of relaxation and recovery as the body returns to a normal state.

Question 14

What is a neuron and what are they made of?

Answer 14

• Neurones are elongated cells consisting of a cell body and long, thin axon.
• Thin projections called dendrites extend from the cell body and connect with other neurones, allowing electrical impulses to pass from one to the other.
• The axons of most neurones are wrapped in an insulating lipid layer called the myelin sheath.

Question 15

What do sensory neurons do?

Answer 15

• Sensory neurons transmit messages from sense receptors, such as
  the eye or nose, to the brain or spinal cord.

Question 16

What do motor neurons do?

Answer 16

• Motor neurons transmit messages from the brain and spinal cord to the muscles or glands.

Question 17

What do relay neurons do?

Answer 17

• Relay neurons allow sensory and motor neurons to communicate with each other.
  –> These relay neurons (or interneurons) lie wholly within the brain and spinal cord.

Question 18

How do you identify the different neurons in the exam?

Answer 18

Sensory – Long dendrites, short axon, looks like a space alien
Relay - short dendrites and short axons
Motor – short dendrites, long axon

Question 19

What is a stimulus?

Answer 19

Stimulus - A change that can be detected e.g. A drawing pin in your chair
Receptor - Something that detects stimuli e.g. Pain receptors in your skin
Effector - Something that makes a response e.g. Muscles in your leg

Question 20

Describe the reflex flow chart

Answer 20

Stimulus –> Receptor –> Sensory neuron –> Relay neuron –> Motor neuron –> Effector –> Response

Question 21

What is synaptic transmission?

Answer 21

• Synaptic transmission is how nerve cells (neurons) communicate with each other.
• When one neuron wants to send a signal to another, it releases chemicals called neurotransmitters into a small gap (synapse) between the two neurons.
• These chemicals then travel across the gap and bind to the receiving neuron, allowing the signal to continue.
• It’s like sending a message from one cell to another through a tiny space.

Question 22

What are the steps of a synaptic transmission?

Answer 22

Synaptic transmission:
1.) Electrical impulses pass down the axon of the first neurone.
2.) Vesicles containing neurotransmitters move towards the pre-synaptic membrane.
3.) Vesicles fuse with the pre-synaptic membrane and release neurotransmitters into the synaptic cleft.
4.) Neurotransmitters diffuse across the synapse and attach to receptors on the post synaptic membrane.
5.) Activity in the receptors causes a change in the second neurone which increase or decreases the likelihood of an action potential in the second neurone.
6.) Neurotransmitter molecules are recycled into the pre-synaptic neurone.
7.) An electrical impulse is then triggered again and travels down to the end of the axon.

Question 23

What are the two different types of neurotransmitters?

Answer 23

• Excitatory
• Inhibitatory

Question 24

What is an excitatory neurotransmitter?

Answer 24

• Excitatory neurotransmitters increase (positively charged) the
  likelihood that an electrical impulse will be triggered in the postsynaptic neuron. (Adrenaline)

Question 25

What is an inhibitatory neurotransmitter?

Answer 25

• Inhibitory neurotransmitters decrease (negatively charged) the
  likelihood that an electrical impulse will be triggered in the postsynaptic neuron. (Serotonin)

Question 26

What are some examples of neurotransmitters that come up in psychology?

Answer 26

• Some neurotransmitters which come up in psychology are dopamine, serotonin, noradrenaline and GABA.

Question 27

What is the role of antidepressants in a synapse?

Answer 27

• Antidepressants help improve mood by affecting the chemicals
  in the brain that transmit signals between neurons.
• In a synapse, antidepressants work by increasing the levels of
  certain neurotransmitters (like serotonin) that are involved in
  mood regulation.
• They do this by blocking the reabsorption (or reuptake) of
  these neurotransmitters back into the sending neuron, allowing
  more of them to be available in the synapse and making it
  easier for signals to pass between neurons.
• This helps improve mood and reduce symptoms of depression.