The Nervous System and the Endocrinne System (Biopsychology) Flashcards
The Human Nervous System
Provides the biological basis of psychological experience.
Can be further divided into the Peripheral and Central Nervous systems.
The Central Nervous System
Central Nervous System:
• controls our bodily functions and psychological processes
Can be further divided into the Brain and Spinal Cord
Peripheral Nervous System
• transmits messages via millions of neurones (nerve cells), to and from the central nervous system
Can be further divided into the Somatic and Autonomic Nervous systems.
Somatic Nervous System
- This is the part of the PNS that is responsible for carrying sensory and motor information to and from the spinal cord
• Is made up of 12 pairs of cranial nerves from the brain, 31 pairs of spinal nerves from the spinal cord and all of their branches
• conscious
Autonomic Nervous System
• transfers information to and from internal organs to maintain life governing vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
• (fight or flight)
• unconscious processes necessary for life
Can be further divided into the Parasympathetic and Sympathetic Nervous systems.
The Brain
• main job is to ensure that life and psychological processing is maintained
• many parts of the brain, some of which are concerned with vital functioning and others which are involved in processes such as problem solving and higher order thinking
• the centre of all conscious awareness. The brain’s outer layer, the cerebral cortex, is highly developed in humans and is what distinguishes our higher mental functions
• the brain is divided into two hemispheres
The Spinal Cord
• Facilitates the transferal of messages to and from the brain to the PNS
• Also responsible for reflex actions
• is an extension of the brain
Sympathetic Nervous System
- anxiety and fear are important for survival because they ac as a mechanism to protect the body against stress and danger
- the sympathetic nervous system controls what has been called the “fight or flight” phenomenon because of its control over the necessary bodily changes needed when we are faced with a situation where we may need to defend ourselves or escape
- slows digestion, inhibits saliva production, increases heat rate, stimulates glucose production, stimulates urination (relaxes the bladder), dilates pupils, dilates bronchi
The Endocrine System
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream
Gland
an organ in the body that synthesises substances such as hormones
Homeostasis
the maintenance of a constant internal environment within the body
Hormones
Chemical substances that circulate in the bloodstream their effects on behaviour can be very powerful.
They affect target cell with receptors for specific hormones.
Pineal Gland
Produces and secretes the hormone melatonin which regulates biological rhythms such as sleep and wake cycles.
Located in the brain
Adrenal Glands
Adrenal glands release adrenaline directly into the bloodstream which prepares the body for fight or flight by constricting blood vessels to the stomach.
This inhibits digestion and increases your heart rate.
Women produce testosterone here.
Is stimulated by ACTH to secrete cortisol.
Is located above the kidneys.
The outer part is called the adrenal cortex (which secretes cortisol to control metabolism of glucose) and the inner part is call the adrenal medulla (which secretes adrenalin and noradrenalin)
Pituitary Gland
Located in the brain and is called the master gland, Controls the release-of hormones from all the other endocrine glands. Also known as the master gland.
Located in the brain, below the hypothalamus (which controls it).
Consists of the anterior and posterior lobes.
The anterior releases ACTH in response to stress, stimulating the adrenal gland.
The posterior releases oxytocin, which is important for childbirth.
Testes
This facilitates the release of the male hormone- testosterone
Testosterone affects aggression, facial hair, sex drive, muscle mass.
Ovaries
this facilitates the release of the female hormones- oestrogen and progesterone
produces eggs
(Evaluations of endocrine system) Gender differences
(beta-bias)
• Taylor et al 2000 found that men usually react to stress with a ‘fight or flight’ response but women may show a ‘tend and befriend’ response
• Oxytocin (a hormone secreted in both men and women) is a response to stress has been shown to make people less anxious and more sociable
• However, male hormones reduce the effects of oxytocin but female hormones oestrogen amplifies it
• Therefore, men re more vulnerable to the adverse health effects of stress and more likely to develop stress related disorders (hypertension and CHD)
• In contrast, women are more likely to ‘tend and befriend’ and this may protect women from stress and this may explain hy women live on average 7.5 years longer than men
(Evaluations of endocrine system) Reductionist
• a person’s response depends on a number of different factors. These include the types of stressor involved, and the way the person interprets (cognitively) the threat. This suggests that this approach may present an oversimplified explanation.
Sensory Neurone
Function:
Unipolar- only transmits messages in one direction
Carries messages from the PNS to the brain and spinal cord (CNS)
Length of Fibres:
Long dendrites and short axons
Relay (interconnecting) neurone
Function:
Multipolar neurones- send and receive messages
Transfers messages from sensory neurones to other interconnecting neurones or motor neurones
Length of fibres:
Short dendrites and short or long axons
Motor Neurone
Function:
Multipolar neurones- send and receive messages
Carries messages from the CNS to effectors such as muscles and glands
Length of fibres:
Short dendrites and long axons
Structure of a Motor Neurone
(refer to diagram)
Cell body: includes a nucleus
Nucleus: the control centre of a cell which contains the chromosomal DNA
Dendrite: receives the nerve impulse or signal from adjacent neurones
Axon: where the electrical signals pass along
Myelin Sheath: insulates/protects the axon from external influences that might effect the transmission of the nerve impulse down the axon
Nodes of ranvier: speed up the transmission of the impulse by forcing it to jump
Terminal buttons: send signals to the adjacent cell
process of synaptic transmission 1
- nerve impulse travels down an axon
- nerve impulse reaches synaptic terminal
- this triggers the release of neurotransmitters
- the neurotransmitters are fired into the synaptic gap
process of synaptic transmission 2
- neurotransmitter binds with receptors on the dendrite of the adjacent neurone
- if successfully transmitted the neurotransmitter is taken up by the post-synaptic neurone
- the message will continue to be passed in this way via electrical impulses
The Reflex arc
a stimulus is detected by sense organs in the peripheral nervous system, which conveys a message along a sensory neurone.
The message reaches the nervous system where connects with a relay neurone. This transfers the message to a motor neurone.
This then carries the message to an effector such as a muscle, which causes the muscle to contract.
Action potential
Occurs when a neurone sends information down an axon, away from the cell body. The action potential is an explosion of electrical activity, meaning that some event (a stimulus) causes the resting potential to move forward.
Resting and Activating states
Resting: the inside is negatively charged compared to the outside
Activating: the inside is positively charged causing action potential
Refer to diagram of synaptic transmission
Reuptake of neurotransmitters
the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal, broken down by enzymes
Excitatory and inhibitory Neurotransmitters
Neurotransmitters can be either excitatory or inhibitory
-excitation only: acetylcholine (ACh), adrenaline
-inhibitory only: serotonin, GABA
Excitatory and Inhibitory synaptic connections
synaptic connections can be excitatory or inhibitory- the difference lies in the action of the neurotransmitter at the postsynaptic receptor
Excitatory- they make it more likely the next neurone will fire
Inhibitory- they make it less likely the next neurone will fire
Effects of excitatory and inhibitory neurotransmitters
If the neurotransmitter is excitatory then the pos synaptic neurone is more likely to fire an impulse as the neurotransmitter increases the positive charge (once the positive charge reaches the threshold, depolarisation occurs and the post synaptic neurone fires)
If the neurotransmitter is inhibitory then the post synaptic neurone is less likely to fire an impulse as it increases the negative charge (the neurotransmitter needs to keep the charge below threshold so that depolarisation does not occur and thus the post synaptic neurone will not fire)
Summation
the process that determines whether/how frequently the neurone will fire- by the combined effects of excitatory and inhibitory signals.
The excitatory and inhibitory influences are summed, if the net effect on the post synaptic neurone is inhibitory, the neurone will be less likely to fire and if the net effect is excitatory, the neurone will be more likely to fire
Parasympathetic Nervous System
Rest and Digest, maintains and conserves body energy and functions
Increases digestion, increases saliva production, decreases heart rate
