nervous system Flashcards
Sensory receptors respond to external/internal stimuli by sending nerve impulses to brain and spinal cord
Sensory input
Brain and CNS process stimuli from receptors all over the body.
Brain prioritizes stimuli, responds appropriately
Integration
The CNS signals muscles (causing contractions) or glands (secretions) and organs
motor and glands
Nervous system is responsible for ____
mental activity
Brain is the control center and helps the body conditions stay stable
Homestasis
Spinal cord and brain
Central Nervous System
Contains most of the cell bodies of neurons, Consists of 100 billion neurons and 1000 billion neuroglia,
CNS
The support and nourishing cells.
Neuroglia
Send electrical & chemical signals
Neurons
Connects to Spinal Cord
Brain Stem
Posterior to Brainstem
Cerebellum
Thalamus, hypothalamus, pituitary and pineal gland, above brain stem
Diencephalon
Spreads over diencephalon, R and L hemispheres, connected.
Cerebrum
Connects hemispheres of brain
corpus callosum
Responsible for right side of body, math, analytrical skills, and speech
Left Hemisphere
Controls left side of body, responsible for music, art, abstract ideas
Right Hemisphere
- Surface of cerebrum, composed of gray matter, cell bodies.
- Convoluted, has no nerve tracts just cell bodies
- Contains billions of neurons arranged in six layers
- Senses, controls voluntary movement and consciousness
- Contains motor areas, sensory areas, and association areas
- Accounts for 40% of brain mass
Cerebral cortex
folds, increase surface area.
Gyri
grooves
Sulci/sulcus
Controls voluntary motor
functions, aggression, moods, smell, personality.
Frontal Lobe
Evaluates sensory input such as
touch, pain, pressure, temp., taste. Involved in math and spatial reasoning.
Parietal Lobe
Responsible for Vision
Occipital Lobe
hearing, smell, memory
Temporal Lobe
Deep to lateral sulcus. Taste, emotions, speech, and possibly awareness of balance and head position in space.
Insula Lobe
Maintains homeostasis by regulating thirst, hunger, sleep, temperature, water balance.
Hypothalamus
receives sensory information (all except smell) integrates & sends to cerebrum. Relay center for sensory information. Involved in arousal, memory and emotions.
Thalamus
Secretes melatonin and regulates the body’s circadian rhythm.
Pineal Gland
The master gland
Pituitary Gland
Second largest structure in the brain. Processes and coordinates movement: critical for balance. Problems with it may be linked to autism
Cerebellum
Oldest, most primitive region of the brain. Consists of medulla oblongata, pons and midbrain. Controls basics: consciousness, sleep, breathing, blood pressure, vomiting.
Brain Stem
Two types of nervous system
Somatic and Automatic
Neurons always arise in CNS (no
ganglion) and synapse onto a skeletal
muscle. Voluntary or involuntary (reflexes)
Somatic Nervous System
Self-governing – not under voluntary control (subconscious); Homeostasis
Autonomic Nervous System
important in an emergency - accelerates heart rate, dilates bronchi, pupils. Norepinephrine (NE) is the neurotransmitter.
Sympathetic division of the ANS
“Rest and digest”. Slows heart-rate, promotes digestion. Acetylcholine is the neurotransmitter
Parasympathetic division of the ANS
structures that encase and protect brain and spinal cord.
Meninges
tough white fibrous connective tissue lies next to skull and vertebrae.
Dura
Closest to brain and spinal cord.
Pia
web-like sturcture of meningies
arachnoid membrane
in between arachnoid membrane, contains cerebralspinal fluid (CSF)
Subarachnoid space
excessive CSF, blockages can occur, ventricles in brain enlarge
hydrocephalus
gap between end buttons and
target (muscle or another neuron). Includes
end bulb and target tissue.
synapse
Mostly nerve endings, few cell bodies, divided into afferent divisions, sensory and efferent.
Peripheral Nervous System
Going to CNS
sensory
Motor, moving away from CNS
efferent
recieve signals from other neurons, tree shaped
dendrites
has nucleus, where signal is generated
cell body
nerve signal is conducted towards axon buttons
axon
axon’s insulation (glial cells)
myelin sheath
unmylenated axon between mylein sheath, speeds up nerve impulse.
nodes of ranvier
(in end bulb) are the chemicals that conduct signal from neuron to target.
Neurotransmitter
long axons bundled together with
connective tissue into cord-like fibers in PNS.
nerves
long axons bundled together in CNS
tracts
a difference in overall charge between inside cell and outside the cell
Resting potential
Each cells resting potential is approximately
-70 millivolts
works by binding to voltage-gated sodium channels & blocking them so action potentials cannot pass from pain receptors.
Novocaine, Lidocaine and
Articaine
Over 100 have been identified, 10 involved in human physiology. ACh and NE
neurotransmitter
Most cells are ____ charged compared to their extracellular environment
negatively charged
The neuron receives a signal from another neuron, initiates
action potential
Action potential converts neurons from
negatively charged to positively charged
which ions are responsible for the action potential?
sodium and potassium
positive change in voltage, caused by sodium entering the cell.
depolarization
return to negative voltage, caused by potassium leaving the cell. sodium channels close, cell returns to normal
repolarization
contain neurotransmitters which are released to transfer signal to muscle or another nueron
axon terminal
A reflex is caused by which NS?
Somatic NS
