Biopsychology

Biopsychology

The ways in which biological factors influence mental processes, emotions and behaviours.

What are the 2 major systems used to gain and respond to information from the environment

The nervous and endocrine system

What diagram is this

The organisation of the human nervous system

What are the divisions/branches of the nervous system

The central and peripheral nervous system

What is the central nervous system (CNS)

It is the system that passes messages to and from the brain and connects nerves to the peripheral nervous system

What are the divisions of the central nervous system

The brain and spinal cord

The brain

The centre of conscious awareness, decision making and is involved in all psychological processes

What is the cerebral cortex

It is found in the brain and is what distinguishes our higher mental functions from those of animals

The spinal cord

It transports messages to and from the brain to the peripheral nervous system and is responsible for reflex actions.

What is the peripheral nervous system

The PNS transmits messages throughout the whole body from the brain and also relays messages back to the brain

What is the PNS made up of

31 spinal nerves, containing millions of sensory and motor pathways

What are the divisions of the peripheral nervous system (PNS)

Autonomic and somatic nervous system

What is the somatic nervous system (SNS)

It is a system that controls voluntary movements, and transmits and receives messages from the senses apart from sight

Why does the SNS not receive message from sight

Because the retina and optic nerve are connected directly to the brain

What are the two components that make up the somatic nervous system

The sensory pathway and motor pathway

What is the sensory (afferent) pathways

They bring sensory information towards the central nervous system

How does the sensory pathways work

• The sensory receptors make up these pathways and trigger nerve impulses (action potentials) in sensory neurons

• These neurons carry the sensory information into the spinal cord (CNS) via the spinal nerves (PNS)

• In the spinal cord, they make synaptic connections on to the relay neurons that carry the information up to the spinal cord, to the brain where it is processed

What is the motor (efferent) pathways

They carry motor commands away from the central nervous system to the effectors

What are effectors and examples

Biological components that produce a response to a stimulus or signal, causing a physical or chemical change e.g. muscles, glands, cells, or molecules

How does the motor pathways work

• The commands needed to move our muscles are formulated in the cerebral cortex of the forebrain

• Then they travel down through the brain and spinal cord to the spinal nerves

• The axons of motor neurons travel in spinal nerves out to the skeletal muscles of the body, allowing the brain to control bodily movement

What is the automatic nervous system (ANS)

It is a system that controls involuntary movements, and transmits and receives messages from the organs

How does the automatic nervous system work

• It’s centres are located in the brain stem and the pathways run down through the spinal cord

• These are then distributed throughout the body by the spinal nerves

What are other functions of the ANS

• Plays a central role in states of bodily arousal

• Responsible for vital functions such as heartbeat, digestions

• It only has motor (efferent) pathways and operates automatically

What are the two branches of autonomic nervous system that helps it carry out its functions

Sympathetic and parasympathetic nervous system

What is sympathetic nervous system (SPNS)

It is involved in “the fight or flight response” and leads to bodily arousal like increased heart rate, blood pressure and a decrease in activity in the digestive system

What is Parasympathetic nervous system (PSNS)

It is involved in “the rest and digest response” and leads to body relaxation like decreased heart rate, psychological calm, lower blood pressure and increase in digestive activity

What is a Neuron

Cells that make up the nervous system and are specialised for transmitting electrical impulses

What is the term for electrical impulses

Action potentials

Features of a neuron

Cell body, dendrites, axon, axon terminal, nucleus, myelin sheath and nodes of Ranvier

Cell body

It is a part of a neuron that contains the nucleus

Nucleus

Where most of the metabolic work of each

Dendrites

They receive action potentials from other neurons and direct these towards the cell body

Axon

It carries the action potentials away from the cell body towards other neurons

Myelin sheath

A fatty substance that covers the axon and increases the speed at which action potentials travel

nodes of Ranvier

Breaks of between 0.2 & 2mm in the myelin sheath that speeds transmission of action potentials as they “jump” from node to node

Axon terminal

Where the neuron will synapse with another neuron or an effector

The three types of neuron

Sensory, relay and motor

Sensory neuron

Carries signals from receptors to spinal cord and brain

Relay neuron

Carries messages from one part of the CNS to another

Motor neuron

Carries signals from the CNS to effectors

Locations of the 3 types of neurons

Sensory and motor is located in the PNS and relay is located in the CNS

What neuron is this

Sensory neuron

How the sensory neuron works

• They receive signals from receptors that detect external stimulation

• These signals enters through the dendrites

• Passes it to the cell body via the axon and onto the axon terminals where they connect to other neurons

Dendrites and axons of sensory neuron

They have long dendrites and short axons

What neuron is this

Relay neuron

How the relay neuron works

They form connections between other neurons

How many relay neurons are in the body

more than 100 billion

Dendrites and axons of relay neuron

They have short dendrites and short axons

  What neuron is this

Motor neuron

How the motor neuron works

• Information enters motor neurons from the dendrites

• It is then passed all the way along the axon terminals

• If the motor neuron connects with a muscle the axon terminal will be called a motor end plate

Dendrites and axons of a motor neuron

They have short dendrites and long axons

Synaptic transmission

The process by which one neuron communicates with another

The process of Synaptic Transmission

• The neurons connect but do not make direct contact as there is a small gap between them called synapse

• Information is passed down the axon of the neuron as an action potential

• Once the action potential reaches the end of the axon it needs to cross the gap between the pre-synaptic and post-synaptic neuron which is the synaptic gap

• In the axon terminal are synaptic vesicles which contains chemicals called neurotransmitters

• When the action potentials reaches these synaptic vesicles, they release neurotransmitters that carry signals that diffuse across the synaptic gap

• They bind to receptor sites on the post-synaptic cell that then becomes activated

• Once the receptor sites have been activated, they either produce excitatory or inhibitory effects on the post-synaptic cell

Excitatory neurotransmitters

They are chemicals like glutamate which cause the neuron to become positively charged, making it more likely to fire

The term for when the neuron becomes positively charged or less negatively charged

Depolarisation

Inhibitory neurotransmitters

They are chemicals like GABA that cause the neuron to become negatively charged, making it less likely to fire

The term for when the neuron becomes negatively charged or less positively charged

Hyperpolarisation

Summation

The addition of positive and negative post-synaptic potentials

Explain the net effect

When the positive and negative potentials a cell receives are summed

Excitation

Occurs when receptor stimulation results in an increase in the positive charge of the postsynaptic neuron which increases the likelihood of the neuron firing

Inhibition

Occurs when receptor stimulation results in an increase in the negative charge of the postsynaptic neuron which decreases the likelihood of the neuron firing

Endocrine system

It secretes the hormones required to regulate many bodily functions into the bloodstream including growth and reproduction

What nervous system is the endocrine system part of?

It is not part of the nervous system but it interacts with the PNS

Glands that make up the endocrine system

Pituitary, pineal, thyroid, adrenal, pancreas and gonads

What does the pituitary gland secrete into the bloodstream and its function

Secretes various hormones that controls reproduction, metabolism, growth and other vital functions

What does the pineal gland secrete into the bloodstream and its function

Secretes hormone melatonin which regulates the body’s internal clock to control sleep-wake cycles

What does the thyroid gland secrete into the bloodstream and its function

• Secretes hormones thyroxine (T4) and triiodothyronine (T3) to regulate metabolism, body temperature, heart rate and growth

• Releases calcitonin to help regulate calcium levels

What does the adrenal gland secrete into the bloodstream and its function

Secretes hormones like adrenaline, noradrenaline etc to regulate a wide range of bodily functions including blood pressure, blood sugar, metabolism and stress response

What does the pancreas secrete into the bloodstream and its function

• Secretes hormones like insulin and glucagon to regulate blood sugar

• Releases somatostatin and pancreatic polypeptide to help control absorption of nutrients and release of digestive hormones

What does the gonads secrete into the bloodstream and its function

Secretes steroid and protein hormones that are essential for developing and maintaining reproductive organs, regulating sexual characteristics and enabling reproduction

What is the endocrine system controlled by?

The hypothalamus

Location of the hypothalamus

In the midbrain and directly connected to the pituitary gland

Function of the hypothalamic hormones

Stimulates the pituitary gland to secrete its hormones

Why is the Pituitary gland classed as the ‘master gland’

Because the hormones secreted by this gland control the functioning of other endocrine glands

Direct effects of adrenaline on the body

• Increases heart rate to increase blood flow to organs and increase movement of adrenaline around the body

• Increases respiration and sweating to regulate temperature

• Increases breathing rate to increase oxygen intake

• Increases blood and oxygen to brain for rapid response planning

• Increases blood to skeletal muscle for physical action

• Diverts blood flow from the skin, kidney and digestive system to increase energy for other essential functions

• Pupil dilation to increase light entry into the eye and enhance vision

General effects of adrenaline on the body

• Prepares the body for action (fight or flight)

• Increase blood supply

• Increases oxygen intake

What happens when the threat has passed

The parasympathetic nervous system returns the body to its resting state

What Taylor et al. (2000) fight or flight research suggests females do

Women are more likely to protect their offspring and form alliances with other women - they adopt a ‘tend and befriend’ response, in dangerous situations