Biopsychology L1-5

Question 1

Describe the central nervous system and its function

Answer 1

• brain and spinal cord
• two main functions: the control of behaviour and the regulation of the body’s physiological processes
• 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 in response.

Question 2

Describe the brain

Answer 2

four main areas:
A) Cerebrum – largest part of the brain. It has four lobes, and is split down the middle into two halves, called the right and left hemisphere.
B) Cerebellum - Responsible for motor skills, balance and coordinating the muscles to allow precise movements.
C) Diencephalon - Contains the thalamus (regulates consciousness, sleep and alertness) and the hypothalamus (regulates body temperature, stress response and hunger and thirst).
D) Brain stem - Regulates breathing and heart rate.

Question 3

Describe the spinal cord

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 co-ordinate voluntary movement.
• The spinal cord is connected to different parts of the body by pairs of spinal nerves, which connect to specific muscles and glands.
• If the spinal cord is damaged, body areas connected to it by nerves below the damage will be cut off and stop functioning.

Question 4

Describe the peripheral nervous system

Answer 4

• The Peripheral Nervous System (PNS) consists of the nervous system throughout the rest of the body (e.g. not the brain or spinal cord).
• The PNS transmits messages via neurons (nerve cells) to and from the CNS.
• The PNS has 2 divisions: The somatic nervous system and the autonomic nervous system.

Question 5

Describe the somatic nervous system

Answer 5

• controls voluntary movements and is under conscious control. It connects the senses with the CNS and has sensory pathways AND motor pathways.
• It controls skeletal muscles. The somatic nervous system is controlled by the motor cortex.

Question 6

Describe the autonomic nervous system

Answer 6

• involuntary (i.e. not under conscious control).
• It ONLY has motor pathways and it controls smooth muscles and the internal organs and glands of the body.
• controlled by the brain stem.

Question 7

Describe the sympathetic nervous system

Answer 7

• This is activated when a person is stressed.
• Heart rate and breathing increase, digestion stops, salivation reduces, pupils dilate, and the flow of blood is diverted from the surface on the skin (fight or flight response).

Question 8

Describe the parasympathetic nervous system

Answer 8

• This is activated when the body is relaxing and so conserving energy.
• Heart rate and breathing reduce, digestion starts, salivation increases, and pupils constrict.

Question 9

Describe the structure of the nervous system (optional: draw it out)

Answer 9

Nervous system:
- central nervous system
- peripheral nervous system

Central nervous system:
- brain (cerebrum, cerebellum, diencephalon containing thalamus + hypothalamus, and brain stem)
- spinal cord (spinal nerves too)

Peripheral nervous system:
- somatic nervous system
- autonomic nervous system

Autonomous nervous system:
- sympathetic nervous system
- parasympathetic nervous system

Question 10

What is a neuron?

Answer 10

Neurons are specialised nerve cells that move electrical impulses to and from the Central Nervous System (CNS).

Question 11

State and describe the parts of a neuron

Answer 11

• Cell Body: Control centre of the neuron.
• Nucleus: Contains genetic material.
• Dendrites: Receives an electrical impulse (action potential) from other neurons or sensory receptors (e.g. eyes, ears, tongue and skin).
• Axon: A long fibre that carries the electrical impulse from the cell body to the axon terminal.
• Myelin Sheath: Insulating layer that protects the axon and speeds up the transmission of the electrical impulse.
• Schwann cells: Make up the myelin sheath.
• Nodes of Ranvier: Gaps in the myelin sheath. They speed up the electrical impulse along the axon.

Question 12

Be able to label a neuron

Question 13

What are the three types of neuron

Answer 13

• sensory neuron
• motor neuron
• relay neuron

Question 14

Describe the role of the sensory neuron

Answer 14

• Sensory neurons are found in sensory receptors.
• They carry electrical impulses from the sensory receptors to the CNS via the PNS.
• Sensory neurons convert information from sensory receptors into electrical impulses. When these impulses reach the brain they are converted into sensations, such as heat, pain etc. so that the body can react appropriately.
• Some sensory impulses terminate at the spinal cord. This allows reflexes to occur quickly without the delay of waiting for the brain to respond.

Question 15

Describe the motor neuron

Answer 15

• Motor neurons are located in the CNS but project their axons outside of the CNS. They send electrical impulses via long axons to the glands and muscles so they can affect function.
• Glands and muscles are called effectors. When motor neurons are stimulated they release neurotransmitters that bind to the receptors on muscles to trigger a response, which leads to movement.

Question 16

Describe the relay neuron

Answer 16

• Relay neurons are found in the CNS. They connect sensory neurons to motor neurons so that they can communicate with one another.
• During a reflex arc (e.g. you put your hand on a hot hob) the relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond (e.g. to lift your hand) without waiting for the brain to process the pain.

Question 17

Be able to draw the sensory, motor, and relay neuron connection

Question 18

What is a synaptic transmission

Answer 18

When neurons transmit electrical impulses, known as action potentials, between the pre-synaptic neuron (the neuron transferring the action potential) and the post-synaptic neuron (the neuron receiving the action potential)

Question 19

What happens when the action potential reaches the pre-synaptic terminal (synaptic transmission)

Answer 19

• When the action potential reaches the pre-synaptic terminal it triggers the release of neurotransmitters (chemical messengers) from sacs on the presynaptic membrane known as vesicles in a process called exocytosis.
• The released neurotransmitter will diffuse across the synaptic cleft (physical gap between the pre-synaptic membrane and post-synaptic membrane) where it binds to specialised post-synaptic receptor sites.

Question 20

What happens after the action potential has been transmitted to the post synaptic neuron

Answer 20

• Synaptic transmission takes only a fraction of a second, with the effects terminated by a process called re-uptake.
• The neurotransmitter is taken back by the vesicles on the pre-synaptic neuron where they are stored for later release. The quicker the neurotransmitter is taken back the shorter the effects.

Question 21

What are the two categories of neurotransmitters, describe them in detail

Answer 21

• Neurotransmitters can be excitatory or inhibitory (most can be both but GABA is purely inhibitory).
• Excitatory neurotransmitters causes an electrical charge in the membrane of the post-synaptic neuron resulting in an excitatory postsynaptic potential (EPSP), meaning that the post-synaptic neuron is more likely to fire an impulse
• Inhibitory neurotransmitters cause an inhibitory postsynaptic potential (IPSP), making it less likely that the neuron will fire an impulse.

Question 22

How do we know if a neuron will fire an impulse

Answer 22

• A neuron can receive both EPSPs and IPSPs at the same time.
• The likelihood that the neuron will fire an impulse is determined by adding up the excitatory and the inhibitory synaptic input. The net result of this calculation, known as summation, determines whether or not the neuron will fire an impulse.
• If the net effect is inhibitory the neuron will not fire, and if the net effect is excitatory, the neuron will fire.

Question 23

Discuss the direction of synaptic transmission

Answer 23

• Information can only travel in ONE direction at a synapse. The vesicles containing neurotransmitters are ONLY present on the pre-synaptic membrane. The receptors for the neurotransmitters are ONLY present on the post-synaptic membrane.
• It is the binding of the neurotransmitter to the receptor which enables the information to be transmitted to the next neuron.
• Diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the pre synaptic membrane to the postsynaptic membrane.

Question 24

What do psychoactive drugs do?

Answer 24

Psychoactive drugs (medication that affects brain function to alter perception, mood or behaviour), such as SSRIs, work by affecting (increasing or inhibiting) the transmission of neurotransmitters across the synapse.

Question 25

Describe in detail the effects of pain medications

Answer 25

• Some pain medications mimic the effects of inhibitory neurotransmitters.
• Stimulation of postsynaptic receptors by an inhibitory neurotransmitter results in inhibition of the postsynaptic membrane. When an inhibitory neurotransmitter binds to the post-synaptic receptors it makes the postsynaptic neuron less likely to fire.
• Due to summation, if inhibitory neurotransmitters are higher than excitatory neurotransmitters they can inhibit an action potential from occurring.
• Therefore, pain medications would decrease the overall activity and reducing brain activity may lead to less pain

Question 26

Be able to draw a synapse

Question 27

Describe the endocrine system
What does it do?

Answer 27

• The endocrine system provides a chemical system of communication in the body via the blood stream.
• Endocrine glands produce and secrete hormones into the bloodstream which are required to regulate many bodily functions.
• major glands: the pituitary gland, and the adrenal glands.
• Each gland produces different hormones which regulate activity of organs/tissues in the body.

Question 28

Describe target cells

Answer 28

• Although hormones come into contact with most cells in the body, they only affect a limited number of cells, known as target cells.
• Target cells respond to a particular hormone because they have receptors for that hormone. When enough receptor sites are stimulated by that hormone there is a physiological reaction.

Question 29

What is the pituitary gland?

Answer 29

• The pituitary gland is located in the brain.
• It produces hormones whose primary function is to influence the release of other hormones from other glands in the body.
• The pituitary gland is controlled by the hypothalamus, a region of the brain just above the pituitary gland.

Question 30

Describe the function of the pituitary gland

Answer 30

• The hypothalamus receives information from many sources about the basic functions of the body. The hypothalamus then sends a signal to the pituitary gland in the form of a RELEASING hormone.
• This causes the pituitary gland to send a STIMULATING hormone into the bloodstream to tell the target gland to release its hormone.
• As levels of this hormone rise in the bloodstream the hypothalamus shuts down production of the releasing hormone and the pituitary gland shuts down secretion of the stimulating hormone

Question 31

What are the two divisions of the pituitary gland

Answer 31

The anterior pituitary gland: releases the hormone called ACTH which regulates levels of the hormone cortisol.

The posterior pituitary gland: responsible for releasing the hormone oxytocin which is crucial for infant/mother bonding

Question 32

What are the two parts of the adrenal gland and where are they located

Answer 32

We have two adrenal glands situated on top of the kidneys. Each adrenal gland is made up of two distinct parts: the Adrenal cortex, and the Adrenal medulla

Question 33

Describe the adrenal cortex

Answer 33

• The outer section of the adrenal gland is called the adrenal cortex.
• It produces the hormone cortisol which is produced in high amounts when someone is experiencing chronic (long-term) stress.
• Cortisol is also responsible for the cardiovascular system, for instance it will increase blood pressure and causes blood vessels to constrict.

Question 34

Describe the adrenal medulla

Answer 34

• The inner section of the adrenal gland is called the adrenal medulla which produces adrenaline, the hormone that is needed for the fight or flight response that is activated when someone is acutely (suddenly) stressed.
• Adrenaline increases heart rate, dilates pupils and stops digestion.

Question 35

Describe the Sympathomedullary Pathway

Answer 35

The Sympathetic Nervous System (SNS) is triggered by the hypothalamus. The hypothalamus also sends a signal to the adrenal medulla (part of the adrenal glands), which responds by releasing a hormone called adrenaline into the bloodstream.

Question 36

Describe adrenaline and its role

Answer 36

• Adrenaline will increase heart rate, constrict blood vessels, increase rate of blood flow, raise blood pressure, divert blood away from the skin, kidneys and digestive system, increase blood supply to the brain and skeletal muscles, and increase respiration and sweating.
• All of this prepares the body for action and fight or flight by increasing blood supply, and therefore oxygen, to skeletal muscles for physical action and increasing oxygen to the brain for rapid response planning.

Question 37

Describe the role of The Parasympathetic Nervous System

Answer 37

When the threat has passed the parasympathetic nervous system dampens down the stress response. It slows down the heartbeat and reduces blood pressure. Digestion, which is stopped when the SNS is active, restarts.

Question 38

What are the strengths of the flight or fight response

Answer 38

• The fight or flight response makes sense from an evolutionary psychology
  point of view because it would have helped an individual to survive by fighting or
  fleeing a threat.
• Studies supports the claim that adrenaline is essential in preparing the body
  for stress. People who have malfunctioning adrenal glands do not have a normal
  fight or flight response to stress

Question 39

What are the weaknesses of the flight or fight response

Answer 39

• Gray (1988) states that the first reaction to stress is not to fight or flight but freeze. This involves the person stopping, looking and listening and being hyper vigilant to danger.
• Taylor (2000) found that females tend and befriend in times of stress. Tend and befriend refers to the protection of offspring (tend) and seeking out social groups for mutual defence (befriend). Women have the hormone oxytocin, which means they are more likely to stay and protect their offspring.
• Von Dawans (2012) has found that even males also tend and befriend. For example, during the 2001 September 11th terrorist attacks both males and females showed tend and befriend as they tried to contact loved ones and help one another.