The Nervous System Flashcards
What are the 3 types of neuron in this system?
Sensory, interneuron and motor.
What does the sensory neuron do?
Determine what you see (eg seeing a glass).
What does the interneuron do?
Associated with the CNS- processing.
What does the motor neuron do?
Determine the behaviour- drink the water.
What does the cerebellum do?
Controls the movement of the body.
What gives the brain its complexity?
The super massive connectivity.
What are the parts in an average nerve cell?
The cell body (soma), dendrites, axon hillock, axon, terminal branches.
What do the dendrites do?
These are the short extensions and the parts that receive the cell information.
What does the axon hillock do?
This sends a wave of electrical activity from the soma down the axon.
What do the terminal branches do?
This is what makes connections to other cells (muscle, nerve, motor neurons).
Why are neurons physiologically demanding?
They need a specific chemical environment to be able to live.
What are the functions of neurons?
-supply nutrients
-support and guide neuronal development
-stabilise neuronal networks
-improve communication speeds
-provide immunological defence
What are the anatomical divisions of the nervous system?
-The Central Nervous System (brain and spinal cord)
-The Peripheral Nervous System (cranial nerves and spinal nerves).
What do cranial nerves control?
Internal organs, from the brain stem.
What do spinal nerves control?
Sensory and motor function.
What are ganglia?
These are relay stations for information (collection of nerve cells).
What are the functional divisions of the nervous system?
-The Somatic nervous system (voluntary)
-The Autonomic nervous system (involuntary).
What are some examples of what the somatic NS control?
Sensory pathways- if you clap your hands, you feel your fingers hit your hand.
What are some examples of what the autonomic NS control?
Things that are automatic- O2 content, pH, temp, blood pressure. It is linked to homeostasis- maintaining an ideal level.
Are sensory PNS afferent or efferent?
Afferent as going towards to the CNS.
What do the somatic motor pathways control?
Skeletal muscle.
What do the autonomic motor pathways control?
Smooth muscle, cardiac muscle, adipose tissue (neuronal control).
Are motor PNS afferent or efferent?
Efferent as going away from the CNS.
What are the effectors?
Things such as muscles that actually do the work (movement).
What are the meninges?
These are a series of membranous layers that have nutritive and protective roles.
Where are the meninges located?
Brain and spinal cord (to protect them).
What is the order of the layers of meninges (inner to outer)?
Pia mater, arachnoid mater, dura mater.
What is the Pia mater?
-Soft mother
-soft, nutritive layer that supports the tissue of the brain.
-highly vascularised, hugs the surface of the brain.
What is the arachnoid layer?
-Firmer than the Pia mater
-Has spidery extensions that extend down to create subarachnoid space filled with cerebrospinal fluid (CSF).
-cerebral arteries and veins, arachnoid trabeculae
What is the dura layer?
-tough layer
-really bonded to the inside of the skull
-in 2 layers (meningeal and periosteal).
What are ventricles in the brain filled with?
CSF.
What are arachnoid granulations?
These are like pressure release valves- release the excess of CSF into venous sinus.
Where is CSF produced?
The choroid plexus.
What is the role of CSF?
-cushioning- protection from trauma
-nutritive (glucose)
-removal of metabolites (urea)
-provides stable ionic environ. (NA+, K+).
Where are there folds in the brain?
There are so many brain cells in humans (need to all fit)- chicken brains are smooth.
What is a gyrus?
This is a ridge on the surface of the brain.
What is a sulcus?
These are trenches between the gyri (shallow groove).
What is a fissure on the brain?
This is a deep sulcus (deeper groove).
What is in grey matter in the brain?
Comprised of neurons, glial cells, blood fibres.
What is in white matter in the brain?
Mainly made up of axons- myosin sheaths cause it to be white.
-fibre tracts, connects different areas of the brain, have both afferent and efferent pathways.
What is the corpus collosum fibre pathway?
Connects the left and right hemispheres.
What is the internal capsule fibre pathway?
Connects higher cortical areas to lower/ spinal cord.
What is the association fibres pathway?
Connects cortical areas in the same hemisphere.
What happens when the corpus collosum is cut during surgery?
One side of the brain doesnt know what the other side is doing (can’t coordinate).
What does the frontal lobe control?
Planning, emotion, mood, behaviour, motor function, smell.
What does the parietal lobe control?
Touch, pain, temperature, sensation (sensory).
What does the occipital lobe control?
Vision.
What does the temporal lobe control?
Hearing, language, memory.
What does the cerebellum control?
Balance, coordination.
What is the insula?
This is a part of the brain under the frontal and temporal lobe.
What are the functions of the insula?
Conscious awareness (pain perception)
-gustation (taste)
-cognitive emotional processing
-audio-visual processing
-interoception (monitoring inside the body)
-homeostatic error detection.
What does the sensory cortex do?
Post central gyrus.
input from skin and proprioceptors (where body is in space), spatial discrimination (how far apart, where things are on body).
What does the motor cortex do?
Pre central gyrus.
motor control of skeletal muscle, motor planning, when activated- individual muscles twitch.
What does the visual cortex do?
This maps visual input, visual recognition.
What does the auditory cortex do?
Pitch, loudness, location, auditory memory and sound recognition.
What does the Wernicke’s area do?
Only on the left side of the brain.
-recognition of words, association with meanings, context.
What does the Broca’s area do?
Only on the left side of the brain.
-motor control of speech, speech planning, language output (allows you to read out words).
-damage- stutter/ problem forming words.
What is the language loop model?
This is the order of areas that allow to read out loud for example.
Visual cortex- receive visual words on page=> Wernicke’s- understand meaning/ context of words=> Broca’s area- say wha you need to say.
What is somatotophy?
The body maps onto the brain surface.
What is the reticular formation?
This is collection of nerve cells and fibres in the central part of the brain stem.
What are the functions of the reticular formation?
-filtering
-control of sleep and consciousness
-modulation of pain
-regulation of CV and resp systems
-somatic motor control (face and head via cranial nerves).
What does the brainstem contain?
-medulla, pons and midbrain
-ascending and descending nerve tracts
-origin of cranial nerves
-reticular formation
What are the functions of the cerebellum?
-control of balance (receives info form inner ear)
-influences posture and muscle tone
-coordination of movement
-motor learning (muscle memory such as knitting whilst watching TV)
What is the sympathetic NS?
The thoracolumbar, respond to threats (middle of spine mostly).
What is the parasympathetic NS?
The craniosacral, rest and digest (above and below symp NS).
In parasympathetic NS, what are the lengths of the ganglions?
The preganglionic fibres are long, postganglionic are short.
In symp NS, what are the lengths of the ganglions?
The preganglionic are short, postganglionic are long.
What does it mean if something if something is myelinated?
Levels of fatty insulation.
What chemical is released from the parasympathetic NS?
ACh (acetylcholine- released on tissues which slows heart rate).
What are splanchnic nerves?
These are nerves either side of vertebral column, receive info from sympathetic ganglion and control viscera.
What is a solar plexus?
This is a group of ganglia that makes up part of the pre vertebral complex.
What are the pre vertebral ganglia?
-celiac ganglia
-superior mesenteric ganglia
-aorticorenal ganglia
-inferior mesenteric ganglia
What does the celiac ganglia control?
Liver, intestines etc.
What does the aorticorenal ganglia control?
Sympathetic control to kidneys and renal system.
What chemical is released from the sympathetic NS?
NE (Norepinephrine/ noradrenaline)- has a role in stress and with effector organs.
What does the adrenal medulla release?
This is the inner part of the adrenal glands and releases adrenaline (80%) and noradrenaline (20%) for the sympathetic NS.
What effects can the fight or flight response have?
-increased blood flow to muscle
-decreased blood flow to gut and skin
-increased cardiac output
-bronchodilation
What does the brain stem control?
Regulates pupil size, heart, blood pressure, airflow, salivation (autonomic functions).
What are the 3 main nuclei involved in brain stem control of respiratory function?
-Pontine nuclei
-ventral respiratory group
-dorsal respiratory group
What does the pontine nuclei do?
Acts like cerebellum, adjusts rate and depth of breathing.
What does the ventral respiratory group do?
Involved with breathing in and out.
What does the dorsal respiratory group do?
This receives sensory information to inform the ventral resp group.
What does the limbic system do?
This is to do with emotional input/ impact of what’s happening (info processing).
What is the enteric nervous system?
This is a branch of the autonomic nervous system alongside sympathetic and parasympathetic.
This controls the function of the small and large intestines (gastrointestinal tract).
