Biopsychology: The nervous system and the endocrine system

- the nervous system, - neurons and synaptic transmission, - endocrine system, - flight or fight response

What is the nervous system?

Nervous system= the network of nerve cells and fibres transmit impulses between parts of the body

What are the two sub-systems that the nervous system is divided in?

Two sub-systems that the nervous system is divided in=

• Central nervous system (CNS)

• Peripheral nervous system (PNS)

What is the CNS?

CNS= the primary command centre for the body

What makes up the CNS?

CNS is made up of the brain and the spinal cord

What does the brain do? (CNS)

Brain= coordinating centre of sensation and intellectual and nervoys activity (command)

What does the spinal cord do? (CNS)

Spinal cord= a bundle od nerve fibres that connect the brain to the rest of the body (communication and reflex action)

What does the peripheral nervous system? (PNS)

PNS= a network of nerves that connects the CNS to the rest of the body

What are the two sub-systems that the PNS is divided in?

Two sub-systems that the PNS is divided in=

• Autonomic nervous system (ANS)

• somatic nervous system (SNS)

What does the autonomic nervous system (ANS) do? (part of the PNS)

Autonomic nervous system (ANS)= control of the body’s involuntary movements and the organ’s functions

• unconscious

What does the somatic nervous system (SNS) do? (part of the PNS)

Somatic nervous system (SNS)= control the body’s voluntary movements and transmits signals to+from the sense and muscles

• conscious

What does the sympathetic nervous system do?

Sympathetic nervous system= responsible for preparing the body for the fight-flight response (“up”)

What does the parasympathetic nervous system do?

Parasympathetic nervous system do= responsible for restoring the body’s resting levels (“down”)

What is the chart for the nervous system?

What is a neuron?

neuron= a nerve cell that transmits electrochemical information

What is the diagram for the motor, relay and sensory neuron?

What is the function of the motor neuron? classic

Function of the motor neuron= collected in the CNS and stretching to the PNS. They carry messages from the CNS to effectors, such as muscles and glands (CNS→ PNS)

What is the length of fibres of the motor neuron?

Length of the fibres in motor neurons= short dendrites and long axons

What is the function of the relay neuron? symmetrical

Function of the relay neuron= collected in the CNS. They transfer messages from sensory neurons to other connected neurons or to motor neurons. (communication)

What is the length of the fibres of the relay neuron?

Length of fibres in relay neurons= short dendrite and short/long axons

What is the function of the sensory neuron? T-junction

Function of the sensory neuron= collected outside of the CNS. They carry messages from the PNS to the spinal cord and brain (PNS→ CNS)

What is the length of fibres in the sensory neuron?

Length of fibres of the sensory neuron= long dendrites and short axons

What do dendrites do?

Dendrites= inputs into the cell

What do axons do?

Axons= outputs from the cell

What is the diagram for the process of synpatic transmission?

What are the stages of synaptic transmission?

Stages of synaptic transmission=

1. Nerve impulse travels down the axon (action potential- electrical signal)

2. Nerve impulse reaches the pre-synaptic terminal button

3. This triggers the release of NTs from the synaptic vesicles where they’re stored (chemical signal)

4. The NTs are released into the synaptic gap

5. The NTs bind with specific receptor sites on the dendrites of the post-synaptic neuron

6. The NT is absorbed into the post-synaptic neuron

7. The message will either continue or stop, depending on the concentrations of different types of NTs (electrical signal)

What is the action potential in synaptic transmission?

Action potential= the impulse that sets the process of synaptic transmission off and is when the cell moves from being negatively to positively charged

What is the lock and key arrangement in synaptic transmission?

Lock and key arrangement in synaptic transmission= specific NTs can only be received by specific receptor sites

What are excitatory and inhibitory NTs?

• Excitatory NTs= make the next cell more likely to fire: depolarisation→ cell moves from being negatively to positively charged/ less negatively charged, due to increased action potential

• Inhibitory NTs= makes the next cell less likely to fire: hyperpolarisation→ more negatively charged, due to a reduced action potential

  • Both types are always present- it is the relative concentrations that push it one way or the other (summation)

Why can neurons only transmit information in one direction at a synapse?

Neurons can only transmit information in one direction at a synapse=

signal always moves from the axon of the pre-synaptic neuron to the dendrite of the post-synaptic neuron as the vesicles that contain the NTs are only in the pre-synaptic neuron and receptor sites are only on the membrane of the post-synaptic neuron

Biological rule- always, only

What is the endocrine system?

Endocrine system= a collection of organs that synthesise and secrete hormones into the bloodstream

What are endocrine glands?

Endocrine glands= the specialised organs that synthesise and secrete hormones into the bloodstream

What are hormones? 

Hormones= biochemical substantces that circulate in the bloodstream in order to target specific organs and processes

What is the diagram of the human body with the glands?

What hormones does the pituitary gland produce?

Pituitary gland produces=

• oxytocin

• TSH

• Adrenocorticotrophic hormone (ACTH)

What does the pituitary gland do?

Pituitary gland is the ‘master gland’ that controls all the other glands

• e.g.

  • TSH→ thyroid gland

    • ACTH→ adrenal gland

What hormone does the thyroid gland produce?

Thyroid gland produces thyroxine

What does the thyroid gland do?

Thyroid gland is involved in the regulation of metabolosm, such as the conversion of food into energy

What hormone do the adrenal glands produce and what are they activated by?

Adrenal glands produce adrenaline

Adrenal glands are activated by=

• noradrenaline (NT) and the sympathetic nervous system

What do the adrenal glands do?

Adrenal glands= responsible for reacting to threat stimuli: via fight-flight response

What hormone does the testes produce?

Testes produce the hormone testosterone

What does the testes do?

Testes= responsible fpr the development of male reproductive system and secondary sex characteristics

What is the flight-or-fight response?

Flight-or-fight response= the way animals and humans respond to stress by becoming physiologically aroused in order to combat or retreat from an aggressor

What are examples of the physiological changes that happen during the flight-or-fight response?

Examples of the physiological changes that happen during the flight-or-fight response=

• increased heart rate

• expansion of airways in lungs

• increased breathing rate

• oxygenated blood primes blood and muscels

• increased blood glucose levels

• decreased pain sensitivity (cortisol)

• halting of salivation and digestion

• evacuation of excess weight in faeces and urine

Outline the role of adrenaline in the flight or fight response

• Adrenaline is released from the adrenal medulla in response to the release of ACTH by the pituitary gland

• Adrenaline causes increased heart rate and breathing rate, causing increased blood flow and pressure

• This increases the supply of oxygenated blood to the brain and skeletal muscles for rapid response planning and physical action

• The endocrine and sympathetic nervous system cause the arousal and the parasympathetic nervous system returns the body to a resting state