Nervous System Flashcards
What is the nervous system responsible for?
perceptions, behaviours, memories and initiates all voluntary movements
What are the 2 parts
Central and Peripheral
What are some function of the nervous system
Sensory and motor impulses (PNS) and CNS is integration
Afferent =
to enter
Efferent =
to exit
effector =
something that will bring change
Nerves =
bundle of axons surrounds by connective tissue and blood vessels in the PNS
Tracts
bundle of axons surrounds by connective tissue and blood vessels in the CNS
Astrocytes functions CNS
support brace and anchor (BBB) and chemical environment for nerve imulses
Oligodendrocytes function CNS
form and maintain myelin sheath around axons for conduction and protection
Microglia function CNS
function as phagocytes
Ependymal cells function CNS
help produce CSF
Schwann cells function PNS
wrap around axon and form a lipid/protein layer.
electrically insulate axons to increase speed of nerve impulse conduction
Grey Matter consists of
Neuroglia cell bodies, dendrites, unmyelinated axons, neuroglia.
White matter consists of
mainly myelinated axons
plasticity =
ability to change
Medulla oblongata contains
nuclei to control vital functions (cardiovascular and respiratory) and nuclei that control non vitals like coughing, sneezing, hiccuping and swallowing.
bulge where axons cross over
Pons contains
ascending and descending axons, axons that connect left and right hemispheres of cerebellum and cerebellum to cerebral cortex
the mid brain is
the reflex centre for visual activities and startle reflex.
produces dopamine.
substantia nigra to basal nuclei
role of brainstem in consciousness
produces melatonin and filters stimulants
Cerebellum function
smooth and coordinate contractions of skeletal muscle.
regulates posture and balance
coordination of skilled movement
communicates with motor areas of cerebral cortex
Thalamus function
major relay station for sensory impulses to cerebral cortex
Hypothalamus 7 functions
Regulate homeostasis
control autonomic nervous system
produces hormones and control pituitary gland
main link between nervous and endocrine systems
regulates body temperature
regulate eating and drinking
regulate circadian rhythm
Epithalamus
contain pineal gland which produces melatonin
Basal Nuclei
part of cerebellum that perform subconscious adjustment and refinements of outgoing movements
Limbic system
‘emotional brain’ controls emotional response and memory processing
corpus collossum
connects 2 hemispheres together
Primary motor area (Anterior)
concours control of precise/skilled voluntary movements of skeletal muscle
long axons project to spinal cord
Premotor area (Anterior)
control sequence of motor activities to achieve complex skilled motor movements
initiate voluntary movement
Brochas speech area (anterior)
directs muscles involved in speech production
Anterior association area (anterior)
controls mood, personality, intelligence, complex learning abilities, initiative, judgement, reasoning intuition, planning for future and development of abstract idea.
Primary somatosensory area
receive nerve impulses from sensory stimulation and proprioceptors.
areas can be modified
somatosensory association area
allows identification of object from memory and past experiences
Wernickes area (Left temporal/parietal)
interpret meaning speech by recognising spoken works
Primary auditory area (Temporal)
receives nerve impulses from ear to determine sounds
Auditory association
identifies sound as speech music noise and stores the memories of sounds.
Primary visual area
receives visual info
visual association area
interprets visual stimuli enabling to recognise faces
Left hemisphere does
right handed control and spoken and written language, numerical and scientific skills
Right hemisphere
left handed control, creative side, generation of mental images
CSF function
mechanical protection, exchange of nutrients, helps maintain homeostasis (pH levels)
5 steps in a reflex
1 activation of receptor
2 sensory neuron produces an impulse that travels along the axon through dorsal root into grey matter of spinal cord
3 information processed at integrating centre (synapse between sensory and motor neuron)
4 motor neuron carries impulses through anterior root of spinal cord
5 effectors create protective response
Define a reflex
fast predictable involuntary response to changes in the internal and external environment.
Somatic reflexes are
in the skeletal muscles
autonomic reflexes occur how
occur without conscious thought or control (glands/muscles)
Vegus nerve (x)
mixed nerve with wide distribution and function sensory input from the skin, external ear, some taste buds, proprioceptors, chemoreceptors and baroreceptors
What is a nerve plexus
Network of converging and diverging nerve fibres formed by spinal nerve
What is the cervical plexus
branches of nerves (C1-5) that supplies parts of head neck shoulders and chest
What does the Brachial plexus serve
C5-T1 entire nerve supply to upper limbs
What does the lumbar plexus serve
L1-4 services genitals and and anterior/medial thigh
What does the sacral plexus serve
L4-S5 and S1-S4 and services buttock, perineum and parts of lower limb
What does the sciatic Nerve serve
(L4-S3) posterior things and lower leg
What are dermatomes
areas of your skin that send most of it sensory input to CNS from single pair of spinal nerves
What are direct pathways
conscious skilled movements with little reflex activity
What are indirect pathways
carry unconsciously movements that are often reflexive
what is an osmoreceptor
senses osmotic pressure in body fluids
what is a chemoreceptor
chemical receptor
what is a mechanoreceptor
touch, pressure, vibration, proprioception,hearing, stretch,
what is a nociceptor
Pain
What is a proprioceptor
senses body position and movement of joints, equilibrium
what is a photoreceptor
detects light that strikes the retina
what is a thermoreceptor
temperature
What is the somatic nervous system
conscious and subconscious control of muscles in the body.
What is the resting state of a cell/polarisation
all channels = closed -ve inside and +ve outside
What is depolarisation
when sodium channels rapidly open and sodium rushes into cell changing membrane potential from -ve to +ve
what is repolarisation
potassium channels open slowly and potassium moves out of the cell turning it back to -ve. Sodium/potassium pumps then follow behind all of that putting sodium outside and potassium back inside,
What is continuous conduction
progressive and gradual depolarisation and occurs with unmyelinated Axons (C nerve fibres)
What is saltatory conduction
when an impulse leaps between nodes of ranvier increasing speed of conduction. occurs with myelinated axons.
3 stages of a chemical synapse
- Nerve impulse arrives at synaptic end bulb opening calcium channels in presynaptic axon
- Calcium triggers neurotransmitter vesicles to move to membrane and release neurotransmitters into synaptic cleft
- Causes opening of channels on postsynaptic cleft allowing extra cellular ions to flow in and restart nerve impulse.
what is a neurotransmitter
chemical substance used by neurons to communicate with other neurons, muscle fibres or glands.
ways to remove neurotransmitter
- Diffusion
- Enzymatic degeneration
- uptake by cells ( active transport)
