The nervous system Flashcards
central nervous system
consists of the brain and the spinal cord
Peripheral nervous system
Includes the cranial and spinal nerves that connect the CNS to other body parts
Effectors
A muscle or gland that can effect change in the body
Somatic nervous system
Motor pathways of the PNS which lead to skeletal muscles
autonomic nervous system
Motor portion of the PNS which operates without conscious effort and involves smooth muscle or cardiac muscle.
Neuron
Nerve cell which is the functional unit within the nervous system.
Soma (cell body)
The part of the nerve cell that contains the cytoplasm and nucleus and from which nerve processes extend.
Dendrite
part of the neuron that receives input from other neurons
Axon (Nerve fibre)
The part of the neuron that conducts an impulse away from the cell body
Neurofilaments
maintain cell shape and ensure proper diameter of the axon
Axon hillock
A cone-shaped thickening that arises from the cell body that acts as the axon.
Multipolar neurons
Have many processes arising from their cell bodies. Only one of each neuron is an exon, the rest are dendrites.
Bipolar neurons
Have only two processes arising from each end of their cell body. One is an axon, and one is a dendrite.
unipolar neurons
Have a single process extending from the cell body. Usually an axon.
sensory neurons
conduct impulses from peripheral body parts into the brain or the spinal cord
interneurones
lie entirely within the brain or spinal cord. They are multipolar and link other neurons. Interneurons conduct impulses from one part of the brain or spinal cord to another.
motor neurons
Multipolar and conduct impulses out of the brain or spinal cord to effectors.
extracellular space
the outside of the cell
Polarity
exhibiting a difference of charges in a given area.
membrane potential
A charge inside of a cell
excitatory stimulus
Opens “chemically gated” Na+ channels. This makes the neuron less negative.
threshold potential
stimulation level that must be achieved to elicit an action potential.
resting membrane potential
the difference of charges that exist between the inside and the outside of the cell at rest.
Synapse
The functional connection between two neurons
Synaptic celft
A narrow extracellular space between two cells at the synapse
neurotransmitters
chemicals that carry out synaptic transmission
neural pathways
the routes impulses follow as they travel through the nervous system
reflex
automatic response to stimuli within or outwith the body
meninges
Layered membranes that lie between the bony coverings and the soft tissues of the CNS and protect the brain and the spinal cord.
Dura matter
the tough outer layer of the meninges
arachnoid matter
delicate, web-like middle layer of the meninges.
Pia matter
inner layer of the meninges that is in direct contact with the brain and spinal cord
spinal cord
Part of the central nervous system extending from the brainstem below the foramen magnum through the vertebral canal.
cervical enlargement
The thickening of the spinal cord in the cervical region of the spinal cord that gives rise to the nerves serving the upper limbs.
Lumbar enlargement
The thickening of the spinal cord in the lumbar region of the spinal cord that gives rise to the nerves serving the lower limbs
Cauda equina
Nervous tissue extends downwards from the intervertebral disc that separates L1 and L2 to become spinal nerves. This is called cauda equina (Horses tail)
Spinal nerve
nerve that arises from the spinal cord and gives rise to peripheral nerves
ascending tracts
any of a number of bundles of axons in the spinal cord that conduct sensory impulses up to the brain.
Descending tracts
Any of a number of bundles of axons that conduct motor impulses from the brain down through the spinal cord.
Longitudinal fissure
A deep groove that separates the brain into two hemispheres.
Gyri
Folds on the brains surface
Sulci
The space between the gyri
Thalamus
Major processing and relay centre for information entering the cerebral hemispheres
hypothalamus
Primary role in homeostasis, body temperature, food and water intake, sleep, memory, and emotional responses
Epithalamus
The epithalamus has two parts the pineal gland (endocrine organ) and a relay centre between the mid brain and limbic system.
Midbrain
The midbrain has an important role in visual and auditory reflexes.
The pons
The pons conducts impulses from the cerebrum to centres in the cerebellum
medulla oblongata
The medulla oblongata is responsible for automatic functions such as respiration, blood pressure, heart rate et cetera. All nerve fibres pass through the medulla oblongata.
cerebellum
responsible for the co-ordination of motor function
autonomic nervous system
The autonomic nervous system functions without conscious effort add regulates the visceral activities that maintain homeostasis
