Nervous systems Flashcards
What is the nervous system made of?
Glial cells and neurons
What is a neuron?
A specific type of cell that is in the nervous tissue, its key function is to receive and process information and send signals to other cells
When does an electrical signal travel down its length?
When a neuron “fires” or produces an action potential
What happens after action potential?
The neuron will release a neurotransmitter onto other cells (typically, or it passes the electrical signal directly into another cell)
Specific features of a neuron
shape, membrane channels & receptors, electrical charge, action potentials & neurotransmitter release.
What are the two factors of the nervous system?
Central nervous system and peripheral nervous system
Central nervous system
brain and spinal cord
Peripheral nervous system
network of nerves that communicate between the CNS and the rest of the body
Info on the central nervous system
the cerebrum is the largest part of the brain and is split into 2 hemispheres, the cerebellum is primarily involved in controlling movement
What does the brain stem do (part of the CNS)
It regulates vital functions such as consciousness, breathing, and temperature control
What does the spinal cord do (part of CNS)
The major conduit of information between the body and the brain
What are the 2 parts within the peripheral nervous system
Somatic nervous system and the autonomic nervous system
Somatic nervous system importance
Sensory info to the brain (afferent: carry information from sensory receptors of the skin and other organs to the central nervous system (i.e., brain and spinal cord)), muscle commands to muscles (efferent neurons carry motor information away from the central nervous system to the muscles and glands of the body)
Autonomic nervous system
Communicates between the brain and organs
Info on somatic PNS
Somatic PNS consists of all the spinal nerves that innervate
the skin, joints, and muscles under voluntary control.
Info on autonomic PNS
consists of the neurons that innervate internally
organs, blood vessels, and glands (i.e. involuntary control).
Afferent neurons
carries information into the CNS
Efferent neurons
carries information away from the CNS
HOW TO REMEMBER EFFERENT AND AFFERENT
sensory input often preceded a motor
response, so A comes before E. Also, E is for Exiting the brain
Spinal nerves
Form the somatic peripheral nervous system, carry somatosensory info into and motor instructions out of the spinal cord, there are 31 pairs
2 parts in the automatic nervous system
Sympathetic system and the parasympathetic system
Sympathetic (ANS)
Arouses, chain of “ganglia” along the spinal cord. flight or fight
Parasympathetic (ANS)
Calms, some ganglia near the target organs
Cranial nerves
Communicate with body parts and brain but bypass the spinal cord
*Part of the peripheral nervous system
* Some somatic (sensory input and motor commands), some
autonomic (e.g., vagus nerve)
2 parts of the central nervous system
Brain and spinal cord
meninges
protected by bony vertebrae, both the brain and spinal cord are surrounded by 3 layers of protective tissue called meninges (pia, arachnoid, and dura mater)
The spinal cord
Carries tactile information from the skin up to the brain (afferent) and sends signals down from the brain to control movements (efferent), these nerves bundle into roots where they enter/exit the spinal cord, the central portion of the spinal cord is gray matter shaped like a butterfly.
Gray matter
It contains the cell bodies of neurons whose axons can cause muscles to contract.
The 4 major structures of the brain stem
Medulla, pons, cerebellum, and midbrain
The midbrain
Contains nuclei that process and direct attention to auditory and visual infromation, the other nuclei are the source of modulatory neurotransmitters like serotonin, norepinephrine, and dopamine, which regulate sleep, arousal, mood, reward, etc.
Cerebellum
“little brain”, 10% of the brains volume, but most of its neurons, function: fine motor control, motor learning, timing, predicting sensory and motor events, among other things
The diencephalon
thalamus and hypothalamus as well as the pineal gland and the pituitary
The thalamus
is a “gateway” or “relay station” for sensory information arriving into the brain before going to the cortex (contains many different nuclei with different functions)
The hypothalamus and associated glands
involved in hormones, motivation, homeostasis, etc
Basal ganglia
decision making, inittiating voluntary movements, among other functions
Amygdala
fear response, emotion
Hippocampus
involved in episodic memory navigation
Cortical lobes
frontal lobe, central sulcus, parietal lobe, occipital lobed, cerebellum, brainstem, temporal lobe, lateral fissure
The neocortex
motor, sensory, vision, audition
gray matter
cell bodies
white matter
myelinated axons
Ventricles
canal and chambers full of cerebrospinal fluid, cerebrospinal fluid is also in the subarachnoid space, forming a cushion around the brain, and in the spinal cord
cerebrospinal fluid production
produced by the choroid plexus (tissue in the lateral ventricles), the circulate around, eventually absorbed into blood vessels
views of the brain
lateral (side profile), dorsal (looking on the top of my head), anterior (forehead), posterior (back of the head)
3 planes of the brain sections
sagital (straight middle of head), horizontal (eye split), coronal (ear to ear split)
bilateral
both sides
isilateral
same sides (two dots on the left for example)
contralateral
opposite sides
glial cells
just as numerous as neurons, more than just “glue”: support, maintain, repair, insulate neurons, and regulate neural activity, problems with glia involved in many neurological disorders
Astrocytes
Regulate chemical content of extracellular fluid, regulate synaptic transmission (suck up neurotransmitters from the synaptic cleft), also respond electrochemically to neurotransmitters, support the blood-brain barrier, regulate blood flow, and probably more
Oligodendroglia
They are in the brain & spinal cord
Schwann cells
they are in the peripheral nerves
Microglia
borne in bone marrow, enter the brain along with blood and immune cells, they respond to damage, clean up dead cells trigger inflammation
Ependymal cells
Lines the central canal of the spinal cord and the and the ventricles of the brain (they help create cerebra-spinal fluid and keep it moving with cilia)
