biopsychopathology Flashcards
what is the nervous system? (2)
- a specialised network of cells in the body and is our primary internal communication system
- it is based on electrical/chemical signals
what are the main two functions of the nervous system?
- to collect, process and respond to info in the environment
- to co-ordinate the workings of different organs and cells in the body
what two subsystems is the nervous system divided into
- central nervous system (CNS)
- peripheral nervous system (PNS)
what is the CNS made up of?
the brain and spinal cord
key info about the brain (4)
- center of all conscious awareness
- cerebral cortex is 3mm thick - only in mammals
- brain is highly developed in humans - distinguishes our higher function
- divided into two hemispheres
key info about the spinal cord (3)
- an extension of the brain
- passes messages to and from the brain and connects nerves to the PNS
- responsible for reflex reactions
what is the role of the PNS (2)
connect the brain and spinal cord to the rest of the body and the external environment. The peripheral nervous system transmits information to and from the CNS through millions of motor and sensory neurons
what is the PNS subdivided into
automatic nervous system - governs vital functions in the body e.g breathing, heart rate, digestion, and stress responses
somatic nervous system - governs muscle movement and receives info from sensory receptors
what is the role of the sympathetic nervous system
sympathetic nervous system - involved with responses that prepare the body for ‘fight of flight’ e.g increases heart rate,blood rate, dilates pupils,
what is the role of the parasympathetic nervous system
parasympathetic system - returns the body to its ‘normal’ resting rate e.g constricts pupils, slows heart rate, stimulates bil release
what is the role of the endocrine system (4)
- a network of glands across the body that secret hormones
- endocrine system works along the CNS
- works slower than the NS but still very effective
- various glands produce hormones which are secreted into the blood stream
what is a gland
an organ that produces and releases substances that perform a specific function in the body.
what is the role of a hormone
chemical messengers that travel in the bloodstream to tissues and organs. Involved with growth, development, metabolism etc
what is the role of the hypothalamus (2)
connected to the pituitary gland and is responsible for stimulating and controlling the release of hormones from the pituitary gland
the hypothalamus is the control which regulates the endocrine system
what is the role of the ‘pituitary gland’ (2)
- ‘master gland’ - hormones released by this gland control/stimulate the release of hormones from other glands in the endocrine system
- divided into the ‘anterior’ (front) and ‘posterior’ (rear) which release different hormones
what is the role of the ‘anterior robe’
anterior robe - releases ACTH which stimulates the adrenal cortex + release of cortisol
what is the role of the ‘posterior robe’
posterior robe - releases oxytocin which is responsible for uterus contractions during childbirth
role of the pineal gland
main hormone is melatonin which is responsible for important biological rhythms including the sleep-wake cycle
role of the thyroid gland
releases thyroxine which is responsible for regulating metabolism
role of the adrenal gland (split into 2 sections)
adrenal medulla - releases adrenaline + noradrenaline which play a role in ‘flight or fight’
adrenal cortex - releases cortisol which stimulates the release of glucose while supervising the immune system
the role of the testes
testes release androgens e.g testosterone
testosterone responsible for the development of male sex characteristics during puberty + muscle growth
the role of the ovaries
release estrogen which controls the female reproductive system
how do the ANS and endocrine systems work together in a ‘fight or flight’ situation (4 steps)
- stressful stimulus the hypothalamus triggers activity in the sympathetic branch of the ANS - ANS changes from resting ‘parasympathetic’ to psychologically aroused state
- adrenaline is released from the adrenal medulla into the bloodstream
- adrenaline triggers physiological changes in target organs in the body and triggers the ‘fight or flight’ response (sympathetic state - dilated pupils, inc heart rate…)
- once threat has passed, the parasympathetic nervous system returns to parasympathetic state + reduces activities of the body
neurons
there are 100 billion neurons in the human nervous system are located in the brain.
by transmitting signals electrically/chemically provide the nervous system with its primary means of communication
what are the 3 types of neurons
sensory neurons, relay neurons, motor neurons
cell body
includes the nucleus (genetic material) of the cell
dendrites
protrude from the cell body, these carry nerve impulses from neighboring neurons towards the cell body
the axon
the axon - carries impulses away from the cell body down the length of the neurons
the myelin sheath
myelin sheath - fatty layer which cover/protects the axon and speeds up electrically transmission of the impulse
nodes of Ranvier
nodes of Ranvier - gaps in the axon - speed up the transmission by forcing it to ‘jump’ across the gaps along the axon
terminal buttons
terminal buttons - at the end of the axon
communicate with the next neurons across the synapse
draw a neuron
draw the endocrine system
location of motor neurons
cell bodies of motor neurons may be in the CNS but they have long axons which form part of the PNS
location of relay neurons
make up 97% of all neurons and most are found in the brain and visual system
location of sensory neurons
are located outside of the CNS, in the PNS in clusters called ganglia
electrical transmission - firing of a neuron (3 steps)
- when neuron is in a resting state, the inside of the cell is negatively charged
- when the neuron is activated by a stimulus, inside of the cell becomes positively charged for a split second causing an action potential to occur
- creates an electrical impulse that travels down the axon towards the end of the axon