BIOPSYCHOLOGY
THE NERVOUS SYSTEM
Nervous system – specialised network of cells, our primary internal communication system:
Collects, processes, and responds to information in the environment.
Coordinates the working of different organs and cells in the body.
It divides into two sub-systems: central nervous system (CNS), peripheral
nervous system (PNS).
THE CENTRAL NERVOUS SYSTEM
Brain and spinal cord.
Passes messages to and from the brain and connects nerves to the PNS.
Brain – centre of all conscious awareness.
Outer cerebral cortex distinguishes our higher mental functions from animals.
It’s divided into 2 hemispheres.
Spinal cord – extension of the brain.
Responsible for reflex actions, e.g. pulling your hand away from a hot plate.
THE PERIPHERAL NERVOUS SYSTEM
PNS transmits messages via millions of neurones (nerve cells) to and from the CNS.
It is subdivided into the…
Autonomic nervous system (ANS) – controls vital functions in the body such as breathing,
heart rate, digestion, sexual arousal, and stress responses.
Without conscious awareness.
Involuntary actions regulated by this system; vital bodily functions need this.
Made up of motor neurones.
Divides into sympathetic and parasympathetic nervous system…
Sympathetic – responses that help us deal with emergencies or perceived threats.
o Neurones from the SNS travel to almost every organ and gland in the body to
produce physiological changes that prepare the body for fight or flight.
o E.g. pupils dilate, heart rate and breathing increase, non-vital functions
inhibited like digestion.
Parasympathetic – restores normal physiological functioning when the threat has
passed.
o E.g. heart rate and breathing slow, blood pressure reduces, digestion begins.
o PNS is involved with energy conservation and digestion, rest and digest.
Somatic nervous system (SNS) – controls muscle movement and receives information
from sensory receptors.
Made of sensory and motor neurones.
Sensory neurones receive info from sensory receptors and relay messages to CNS.
Connects the CNS to the senses.
Motor neurones relay messages from the CNS to other areas of the body, control
voluntary muscle movement and reflex actions.
THE ENDOCRINE SYSTEM
Network of glands throughout the body that make and secrete chemical messengers called
hormones.
, BIOPSYCHOLOGY
Works alongside the nervous system to control vital functions in the body.
It acts slower than the nervous system, but has widespread, powerful effects.
GLANDS AND HORMONES
Gland – organ in the body that produces substances such as hormones.
Hormones – chemical messengers that regulate the activity of cells of organs in the body by
travelling through the bloodstream.
Hormones are secreted into the bloodstream and affect any cell in the body with a
receptor for that hormone.
Most hormones affect cells in several organs or the entire body, powerful responses.
The main endocrine gland is the pituitary gland in the brain, as it controls the release
of hormones from all other endocrine glands in the body.
Endocrine gland Hormones released Role
Controls release of
Pituitary gland LH, FSH, oxytocin hormones from other
glands.
Prepares the body for fight
Adrenal glands Adrenaline, noradrenaline or flight, lowers sensitivity to
pain, heart rate quickens.
Production of eggs and sex
Ovaries Oestrogen, progesterone
hormones.
Produces sperm and male
sex hormones, develops
Testes Testosterone
male characteristics such as
facial hair, lower voice.
ENDOCRINE AND AUTONOMIC NERVOUS SYSTEM TOGETHER: FIGHT OR FLIGHT
The endocrine and autonomic nervous system often work parallel to each other.
E.g. in a stressful event, a stressor is perceived, the hypothalamus triggers activity in
the sympathetic branch of the autonomic nervous system.
The ANS changes to the sympathetic state when physiologically aroused. Adrenaline
is released from the adrenal medulla into the blood stream.
This triggers physiological changes in the body creating physiological arousal.
This happens in an instant when the threat is detected and is an automatic reaction.
Once the threat passes, the PNS returns the body to its resting state.
The parasympathetic branch of the ANS works in opposition to the sympathetic
nervous system. It reduces activities of the body that were increased by the
sympathetic branch – rest and digest.
Increased blood pressure when this is repeatedly activated can cause heart disease.
THE STRUCTURE AND FUNCTION OF NEURONES
Neurones transmit signals electrically and chemically so the nervous system can
communicate.
TYPES OF NEURONE
Sensory neurones – carry messages from the PNS to the CNS. Long dendrites, short
axons.
Relay neurones – connect sensory neurones to the motor and other relay neurones. Short
dendrites and long axons.
, BIOPSYCHOLOGY
Motor neurones – connect the CNS to the effectors, e.g. muscles and glands. Short
dendrites and long axons.
THE STRUCTURE OF A NEURONE
Cell body – includes a nucleus, with genetic material of the cell.
Branch-like structure called dendrites come out of the cell body, they carry nerve
impulses from neighbouring neurones towards the cell body.
Axon – carries impulses away from the cell body down the neurone. It is covered in a
fatty layer – myelin sheath – that protects the axon and speeds electrical
transmission of the impulse.
The myelin sheath is split up by gaps called nodes of Ranvier which speed up
transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.
Terminal buttons – at the end of the axon and communicate with the next neurone
in the chain across the synapse.
ELECTRICAL TRANSMISSION – FIRING OF A NEURONE
When a neurone is in a resting state in the cell, it is negatively charged.
When this neurone is activated by a stimulus, the inside becomes positively charged,
causing an action potential to occur.
This creates an electrical impulse that travels down the axon to the end of the
neurone.
SYNAPTIC TRANSMISSION
CHEMICAL TRANSMISSION – SYNAPSES
Neurones communicate with each other in groups called neural networks.
THE NERVOUS SYSTEM
Nervous system – specialised network of cells, our primary internal communication system:
Collects, processes, and responds to information in the environment.
Coordinates the working of different organs and cells in the body.
It divides into two sub-systems: central nervous system (CNS), peripheral
nervous system (PNS).
THE CENTRAL NERVOUS SYSTEM
Brain and spinal cord.
Passes messages to and from the brain and connects nerves to the PNS.
Brain – centre of all conscious awareness.
Outer cerebral cortex distinguishes our higher mental functions from animals.
It’s divided into 2 hemispheres.
Spinal cord – extension of the brain.
Responsible for reflex actions, e.g. pulling your hand away from a hot plate.
THE PERIPHERAL NERVOUS SYSTEM
PNS transmits messages via millions of neurones (nerve cells) to and from the CNS.
It is subdivided into the…
Autonomic nervous system (ANS) – controls vital functions in the body such as breathing,
heart rate, digestion, sexual arousal, and stress responses.
Without conscious awareness.
Involuntary actions regulated by this system; vital bodily functions need this.
Made up of motor neurones.
Divides into sympathetic and parasympathetic nervous system…
Sympathetic – responses that help us deal with emergencies or perceived threats.
o Neurones from the SNS travel to almost every organ and gland in the body to
produce physiological changes that prepare the body for fight or flight.
o E.g. pupils dilate, heart rate and breathing increase, non-vital functions
inhibited like digestion.
Parasympathetic – restores normal physiological functioning when the threat has
passed.
o E.g. heart rate and breathing slow, blood pressure reduces, digestion begins.
o PNS is involved with energy conservation and digestion, rest and digest.
Somatic nervous system (SNS) – controls muscle movement and receives information
from sensory receptors.
Made of sensory and motor neurones.
Sensory neurones receive info from sensory receptors and relay messages to CNS.
Connects the CNS to the senses.
Motor neurones relay messages from the CNS to other areas of the body, control
voluntary muscle movement and reflex actions.
THE ENDOCRINE SYSTEM
Network of glands throughout the body that make and secrete chemical messengers called
hormones.
, BIOPSYCHOLOGY
Works alongside the nervous system to control vital functions in the body.
It acts slower than the nervous system, but has widespread, powerful effects.
GLANDS AND HORMONES
Gland – organ in the body that produces substances such as hormones.
Hormones – chemical messengers that regulate the activity of cells of organs in the body by
travelling through the bloodstream.
Hormones are secreted into the bloodstream and affect any cell in the body with a
receptor for that hormone.
Most hormones affect cells in several organs or the entire body, powerful responses.
The main endocrine gland is the pituitary gland in the brain, as it controls the release
of hormones from all other endocrine glands in the body.
Endocrine gland Hormones released Role
Controls release of
Pituitary gland LH, FSH, oxytocin hormones from other
glands.
Prepares the body for fight
Adrenal glands Adrenaline, noradrenaline or flight, lowers sensitivity to
pain, heart rate quickens.
Production of eggs and sex
Ovaries Oestrogen, progesterone
hormones.
Produces sperm and male
sex hormones, develops
Testes Testosterone
male characteristics such as
facial hair, lower voice.
ENDOCRINE AND AUTONOMIC NERVOUS SYSTEM TOGETHER: FIGHT OR FLIGHT
The endocrine and autonomic nervous system often work parallel to each other.
E.g. in a stressful event, a stressor is perceived, the hypothalamus triggers activity in
the sympathetic branch of the autonomic nervous system.
The ANS changes to the sympathetic state when physiologically aroused. Adrenaline
is released from the adrenal medulla into the blood stream.
This triggers physiological changes in the body creating physiological arousal.
This happens in an instant when the threat is detected and is an automatic reaction.
Once the threat passes, the PNS returns the body to its resting state.
The parasympathetic branch of the ANS works in opposition to the sympathetic
nervous system. It reduces activities of the body that were increased by the
sympathetic branch – rest and digest.
Increased blood pressure when this is repeatedly activated can cause heart disease.
THE STRUCTURE AND FUNCTION OF NEURONES
Neurones transmit signals electrically and chemically so the nervous system can
communicate.
TYPES OF NEURONE
Sensory neurones – carry messages from the PNS to the CNS. Long dendrites, short
axons.
Relay neurones – connect sensory neurones to the motor and other relay neurones. Short
dendrites and long axons.
, BIOPSYCHOLOGY
Motor neurones – connect the CNS to the effectors, e.g. muscles and glands. Short
dendrites and long axons.
THE STRUCTURE OF A NEURONE
Cell body – includes a nucleus, with genetic material of the cell.
Branch-like structure called dendrites come out of the cell body, they carry nerve
impulses from neighbouring neurones towards the cell body.
Axon – carries impulses away from the cell body down the neurone. It is covered in a
fatty layer – myelin sheath – that protects the axon and speeds electrical
transmission of the impulse.
The myelin sheath is split up by gaps called nodes of Ranvier which speed up
transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.
Terminal buttons – at the end of the axon and communicate with the next neurone
in the chain across the synapse.
ELECTRICAL TRANSMISSION – FIRING OF A NEURONE
When a neurone is in a resting state in the cell, it is negatively charged.
When this neurone is activated by a stimulus, the inside becomes positively charged,
causing an action potential to occur.
This creates an electrical impulse that travels down the axon to the end of the
neurone.
SYNAPTIC TRANSMISSION
CHEMICAL TRANSMISSION – SYNAPSES
Neurones communicate with each other in groups called neural networks.
