nervous system 1 and 2 Flashcards
CNS
brain and spinal cord
what connects the hemispheres of the brain
corpus callosum
what are the three parts of the brain
forebrain
midbrain
hindbrain
sagital section
viewpoint as though cutting down corpus callosum
coronal section
viewpoint as if cutting through brain from ear to ear
horizontal section/plane
viewing brain cut horizontally, from eyes to occipital lobe
dorsal
upper
ventral
lower
medial
towards middle of brain
lateral
towards outside of brain
anterior
front of brain
posterior
back of brain
hindbrain
-connects spinal cord to cortex
-controls HR, breathing, BP, digestion, coordination of movement, posture and sleep patterns
what substructures are within the hindbrain
medulla: connects brain and spinal cord, associated with nerve signals
pons: relay from forebrain to cerebellum, sleep, respiration, swallowing, bladder control
reticular formation: mass of nerve cells and fibres primarily in brain stem
cerebellum: known as ‘little brain’, higher cog. functions, integrates sensory info, voluntary smooth movement (balance), modification of behaviour with experience
midbrain
-known as relay station
-connects brain stem to forebrain
-coordinates sensory info for visual and auditory reflexes like tracking
midbrain substructures
tectum and tegmentum
forebrain
-higher level cog. processing
-controls cog. sensory and motor function: sleeping, maintaining temp., movements and emotions etc
structures within forebrain
-cerebral cortex
-diencephalon (thalamus and hypothalamus)
-limbic system ( amygdala and hippocampus etc)
what are the lobes of the cerebral cortex
frontal: planning, decisions, personality
parietal: touch, temp., pain
temporal: auditory, speech, language
occipital: vision
what is a gyrus
protruding ridges or folds on the cerebral cortex
what is a sulcus + fissure
a groove in the brain (inside one of the wrinkles on surface of cerebral cortex)
fissure = deep groove in surface of brain e.g separating the two hemispheres
what is the role of the thalamus in the diencephalon
processing, relay centre, all sensory modalities (apart from smell), arousal, awareness, motor function, memory
what is the role of the hypothalamus in the diencephalon
controls ANS, hormone release, homeostasis (eating, drinking, temp., fight/flight)
what is included in the limbic system and what are its roles
-amygdala, cingulate gyrus/cortex, parahippocampul gyrus, olfactory tract
-memory, learning, motivation
-influences endocrine and ANS
-links subcortical structure and the cerebral cortex
role of the basal ganglia
motor control, learning, executive function
-irregular output can cause huntingtons, parkinsons
role of spinal cord
allows voluntary and involuntary motions of muscles and perception of senses
reflex pathway processes in spinal cord not brain
what are the two branches of the PNS
somatic and autonomic
somatic NS
muscle control of body, voluntary and involuntary (reflexes), how we interact with external world
autonomic NS
bodily functions not consciously directed e.g breathin, HR, digestion
branches in sympathetic (prepares for fight/flight) and parasympathetic (turns off fight or flight)
anatomy of neurons
soma
-dna stored in nucleus
-metabolic centre of cell (proteins generated)
-info processed here
dendrite
-receives info from other neurons
-branch like fibres
axon
-transmitter of action potentials to other neurons
-terminal buttons release neurotransmitters
sensory neurons
bring info to CNS from body
have long dendrites and long axons
interneurons
associate sensory and motor neurons
activity in CNS
short axon
motor neuron
from CNS to muscles (effectors)
long axon has myelin sheath
what are glial cells
support cells in the NS
maintain homeostasis
produce myelin
protect neurons
myelination
axons myelinated by Schwann cells (type of glial cells)
gaps are nodes of ranvier allowing saltatory conduction
lipid rich
speeds up rate of conduction
what happens if myelination is damaged
multiple sclerosis = breakdown of myelin sheath
changes in sensation, muscle weakness, difficulties with coordination, fatigue
grey matter
densely packed cell bodies for processing
grey inner section of spinal cord and outer section of the brain
white matter
axons and myelination showing communication occurs here
what is the direction of neural transmission
dendrite - soma - axon - terminal buttons
what is the synapse
tiny gap between pre and post synaptic cell where neurotransmitters are released
what is the resting potential and how is it maintained
-70mV
-maintained by sodium potassium voltage gated channels
-pumps 3Na+ out for every 2K+ in so inside neuron is more negative than outside the cell
what are the three types of channels
voltage gated channels: e.g K+, Na+, when cell reaches certin charge the channel opens allowing ions into cell
ligand gate: a molecule on outside of cell (e.g neurotransmitter) binds to the channel causing the gate to open
tension gate: gates that are pulled apart by physical movement e.g pulling at the skin
what is an action potential
quick change of charge in a neuron
what is the process of an action potential
- cell loses its negative charge so becomes more positive, reaching threshold (depolarisation), triggering action potential
- cell becomes negatively charged again (repolarisation)
- temporarily becomes more negative than resting potential (hyperpolarisation)
after an action potential on the pre synaptic cell, what happens to the ligand gates of the post synaptic cell
neurotransmitter binds to gates on dendrites of post synaptic neuron, positive ions enter cell changing potential from negative to less negative
what is the threshold for an action potential
-55mV
where are the neurotransmitters stored
in vesicles in pre synaptic neuron
excitatory response
neurotransmitters open up ligand gate causing positive ions to enter post synaptic neuron, leading to an action potential
inhibitory response
neurotransmitters do not open the ligand gates of post synaptic cell so there is no action potential
acetylcholine
muscle contraction, memory
dopamine
smooth controlled movements, attention, memory, pleasure
serotonin
sleep regulation, dreaming, mood, arousal, depression, anxiety
noradrenaline
alertness, state of arousal
gamma amino butyric acid (GABA)
inhibitory effect, anxiety, muscle relaxation
what is the endocrine system
second messaging system
longer lasting slower messages
coordinates NS
what are water soluble hormones
dissolve in water
cannot dissolve through cell membrane so bind to receptors on outside of membrane
what are fat soluble hormones
can dissolve in fats
dissolve through cholesterol in cell membrane so hormones can pass through membrane and bind to receptors inside target cell
