Biopsych Flashcards
what are the 2 main functions of the nervous system
- to collect, process and respond to information in the environment
- to coordinate the working of different organs and cells in the body
what are the structures and functions of the central nervous system (CNS)
- the CNS is made up of the brain and the spinal cord
- the brain is the centre of all conscious awareness
- the outer layer of the brain, the cerebral cortex, is highly developed in humans and is what distinguishes our higher mental functions from those from those of animals
- the spinal cord is an extension of the brain and is responsible for reflex actions
- it passes messages to and from the brain and connections nerves to the PNS
what is the structure and function of the peripheral nervous system (PNS)
- the PNS transmits messages, via millions of neurons, to and from the nervous system
- the PNS is further sub divided into the autonomic nervous system (ANS) and the somatic nervous system (SNS)
what is the autonomic nervous system
the ANS governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress response
what is the somatic nervous system (SNS)
the SNS controls muscle movement and receives information from sensory receptors
the \autonomic nervous system is subdivided into the
- sympathetic nervous system
2. parasympathetic nervous system
what are the key function of the endocrine system
the endocrine system works alongside the nervous system to control vital functions in the body through the action of hormones
it works much more slowly than the nervous system but has widespread and powerful effects.
what are glands and what do they do
glands are organs in the body that produce hormones.
what is the major endocrine gland
the major endocrine gland is the pituitary gland located in the brain. it is called the master gland because it controls the release of hormones from all the other endocrine glands in the body.
what are hormones
hormones are secreted into the bloodstream and affect any cell in the body that has a specific receptor for it
thyroxine
a hormone produced by the thyroid gland affects cells in the heart and also cells throughout the body which increase metabolic rates. this in turn affects growth rates.
what does the endocrine system work in parallel with
the autonomic nervous system
what happens to the endocrine system and the ANS during a stressful event
- when a stressor is perceived, the hypothalamus triggers activity in the sympathetic branch of the ANS. the ANS changes from its normal resting state (parasympathetic) to the physiologically aroused sympathetic state
- the stress hormone adrenaline is released from the adrenal medulla in to the blood stream
- adrenaline triggers physiological changes in target organs in the body. the fight or flight response
- once the threat has passed the parasympathetic nervous system returns the body to its resting state.
what is the effect of adrenaline
increased heart rate
dilation of the pupils
decreased production of saliva
the effects of the sympathetic state
readies body for fight or flight
- increases heart rate
- increases breathing rate
- dilates pupils
- inhibits digestion
- inhibits saliva production
- stimulates urination
the effects of the parasympathetic state
rest and digest
- decreases hear rate
- decreases breathing rate
- constricts pupils
- stimulates digestion
- stimulates saliva production
where are the majority of nervous cells located
there are 100 billion nerve cells in the nervous system,
80% are located in the brain
what are the 3 types of neurons
- sensory neurons
- relay neurons
- motor neurons
what is the sensory neuron
carries messages from the PNS to the CNS.
they have short dendrites and long axons
what are relay neurons
connect sensory neurons to motor or other relay neurons.
they have short dendrites and short axons
what are the motor neurons
connects the CNS to effectors such as muscles and glands. they have short dendrites and long axons
what do all neurons contain
- cell body
- dendrites
- axon: myelin sheath and nodes of ranvier
- terminal buttons
what are dendrites
branch like structures that protrude from the cell body. these carry nerve impulses from neighbouring neurons towards the cell body
what is the axon
carries the electrical impulses away from the cell body down the length of the neurons.