Unit 4 Objectives Flashcards
Describe the major functions of the nervous system.
- sensing functions
- analyzing and interpreting
- motor functions
List the structures of both the central and peripheral nervous systems.
central: the brain and spinal cord
peripheral: everything else
Explain the major differences between the three functional divisions of the nervous system.
CNS: command center, processes info and initiates responses
PNS: connects CNS to the rest of the body
ANS: regulates involuntary movements
Define neuron
excitable cells responsible for sending and receiving signals as action potentials
what are the main components of a neuron
cell body (soma), dendrites, axon, myelin sheath, nodes of ranvier, and axon terminals
define dendrites
branches off cell body, grab signals and sends them to cell body
define axons
a long tail coming off soma, send signals away from soma to neurons or muscles(can generate action potentials)
define myelin sheath
fatty covering around axon, helps the signals move along the axon faster
define nodes of Ranvier
the gaps in the myelin sheath, which helps the signal jump along the axon faster
define axon terminals
bulbs at the end of the axon, release chemicals to send a signal out
what are the different variations of neurons
sensory neurons, motor neurons, and interneurons
describe sensory neurons
they have long dendrites and short axons; this allows them to cover more ground and send out signals very quickly (found outside CNS)
describe interneurons
found entirely inside CNS; have short dendrites and axons; are connectors between sensory and motor functions; and allow for quick communication for fast reflex reactions
describe motor neurons
have long axons and short dendrites; found within CNS; long axons allow for sending signals over long distances
what are the 4 types of CNS neuroglial cells
astrocytes, oligodendrocytes, microglia, and ependymal cells
what are the 2 types of PNS neuroglial cells
Schwann cells and satellite cells
describe astrocytes
star shaped cells with many branches; supports and protects neurons, regulates environment around neurons; the branches allow astrocytes to have physical support and allows them to wrap around capillaries to protect the BBB
describe oligodendrocytes
cells with multiple branches that wrap around nerve fibers; produces myelin; their bulbous body and multiple processes allows them to myelinate and protect many axons at once
describe microglia
small cells with branching processes; the immune system of the brain, removes damaged cells and fights infection; their structure allows them to respond and detect defects, and their ability to change shape enhances their surveillance and defense functions
describe ependymal cells
cuboidal cells with cilia; produces cerebrospinal fluid; they move the CSF through our system with their cilia
describe Schwann cells
elongated cells that wrap around nerve fibers, this allows them to produce myelin effectively in the PNS. they only wrap around one axon, unlike oligodendrocytes
describe satellite cells
flattened cells, which allows them to effectively wrap around and protect nerve cell bodies in the ganglia
Describe the myelin sheath
a protective covering that surrounds and insulates axons. speeds up signal transmission
compare and contrast myelination in the CNS vs the PNS
- PNS is myelinated through Schwann cells while
CNS is through oligodendrocytes - Schwann cells only cover one axon but can
myelinate and regenerate nerves much faster - Oligodendrocytes cover many axons at once
but myelinate and regenerate nerves much
slower
Define ion channel
a gate in the cell membrane that controls the flow of charged particles called ions in and out of the cell; selects what ions to allow in to control the electrical activity of cells
describe voltage-gated ion channels
These ion channels open and close in response to changes in the electrical voltage across the cell membrane; crucial for generating action potentials
describe ligand-gated ion channels
These ion channels open and close in response to the binding of specific chemical molecules called ligands; they are involved in synaptic transmission, where ligands released from one neuron bind to another neuron, making the channel open and generating electrical signals
describe mechanically-gated ion channels
these channels open and close in response to physical force such as pressure or stretching of cell membrane; found in sensory neurons
describe leak channels
constantly open and allow ions to pass constantly; maintains resting membrane potential, contributes to electrical gradient
how do ion channels contribute to the resting action potential
they only allow certain ions in and out. cells at their resting state are negatively charged and to maintain that they release Na+ and take in K-
describe local potential
- started by small stimuli
- strength depends on stimulus strength
- spreads passively, weakens as it goes
- can trigger action potentials
- lasts only while stimulus is present
describe action potentials
- started by strong enough stimulus to reach a
threshold - always same strength regardless of stimulus
- doesn’t weaken as it travels
- always triggers an action potential
- lasts a fixed amount of time (1-2 milliseconds)
describe depolarization
At the start, the voltage suddenly rises. This is depolarization. It’s like the neuron’s electrical charge becoming more positive, which triggers the action potential
describe repolarization
After reaching the peak, the voltage starts to drop. This is repolarization. The neuron’s charge is returning to its normal negative state
describe hyperpolarization
Sometimes, the voltage goes a bit lower than normal. This is hyperpolarization. The neuron becomes even more negatively charged than usual before it goes back to its resting state
. Compare and contrast continuous and saltatory conduction
BOTH: invlolve action potentials across axon;
nerve impulses are transmitted
CONTINUOUS: actional potential spreads the
whole lenght of axon; is much slower;
happens in umyelinated axons; requires
more energy as ion channels open and close
along entire axon
SALTATORY: action potential jumps across nodes
of ranvier; is much quicker; occurs in
myelinated axons; requires less energy as ion
movement is concentrated on nodes of
Ranvier
Explain how axon diameter and myelination affect conduction velocity
bigger axons mean faster signals and myelin makes signals travel faster by skipping myelinated sections
Compare and contrast electrical and chemical synapses.
TRANSMISSION: electrical uses channels, while
chemical uses neurotransmitters
SPEED: electrical is much faster
DIRECTION: electrical can go both directions,
while chemical can only go from sending to
receiving.
PLASTICITY: chemical can change over time;
electrical rarely does
Describe the events of chemical synaptic transmission in chronological order
- action potential arrival: action potential
reaches the end of the presynaptic terminal - calcium rush: calcium ions rush into the
presynaptic terminal - release of neurotransmitters: calcium triggers
neurotransmitters to be released from vesicles - neurotransmitter diffusion: Neurotransmitters
travel across the presynaptic cleft to reach the
postsynaptic membrane - binding to receptors: neurotransmitters attach
to receptors on postsynaptic membrane - postsynaptic response: the receptors being
activated cause a change in the postsynaptic
neuron
6.5. they can either be excitatory (neuron is more
likely to send signal) or inhibitory - signal termination: Neurotransmitters are
removed from the synaptic cleft (through
diffusion, being absorbed or broken down by
enzymes) - postsynaptic recovery: the postsynaptic
neuron returns to resting state
Define excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP).
EPSP makes neurons more likely to fire while IPSP makes them less likely
List the three ways synaptic transmission is terminated
reuptake, degradation, and diffusion
Discuss the relationship between a neurotransmitter and its receptor
neurotransmitters are like a special key that can only fit into certain receptors (locks)
what are the 4 neurotransmitters
amino acids, monoamines, acetylcholine, and neuropeptides
what are amino acids
glutamate (excitatory), GABA (calming), and glycine (inhibitory)
what are monoamines
dopamine (award and mood), serotonin (mood and sleep), norepinephrine (alertness), epinephrine (stress response)
what is acetylcholine
CNS: memory and attention
PNS: movement and heart rate
what are neuropeptides
proteins that regulate things like pain, stress, mood, and social bonding
(endorphins, oxytocin, and substance P)
what is white matter in the brain and spinal cord
BRAIN: carries signals between gray matter, the inner part
SPINAL CORD: the outer part carrying signals between brain and body
what is gray matter in the brain and spinal cord
BRAIN: the outer layer; thinking and perception
SPINAL CORD: the inner part handling sensory information and movement coordination.
Describe the function of the cerebrum and its overall structure
the command center of the brain; the largest part of your brain sitting at the top
Describe the function of the frontal lobe
MOTOR: moves voluntary muscles
SENSORY: helps plan movements
Describe the function of the parietal lobe
MOTOR: plans hand or finger movements
SENSORY: Processes feelings like touch, pain, and where your body is in space
Describe the function of the temporal lobe
MOTOR: doesn’t rlly control movement
SENSORY: helps you hear, memory, and understanding language
describe the function of the occipital lobe
MOTOR: doesn’t control movement
SENSORY: processes what you see
describe the function of the insular lobe
MOTOR: not main for movement
SENSORY: senses things like feelings, pain, temperature, and emotions
where is the location of the limbic system
deep within the brain, near the center
what are the functions of the limbic system
It handles emotions, memories, and basic instincts like eating and feeling motivated.
where is the location of the diencephalon?
the middle of the brain, just below the cerebrum
what are the functions of the diencephalon?
helps relay sensory information and helps regulate sleep, thirst, hunger, and body temp
what are the four components of the diencephalon
thalamus, hypothalamus, epithalamus, and subthalamus
describe the function of the thalamus
sorts and send sensory info to the right areas of the brain
describe the function of the hypothalamus
helps control things like body temperature, hunger, thirst, and sleep; also manages hormones and plays a role in emotions
describe the function of the epithalamus
includes the pineal gland which produces melatonin; regulates sleep-wake cycle
describe the function of the subthalamus
helps coordinate smooth movements and prevent involuntary movements
describe the function of the cerebellum
helps control movement, balance, and coordination; also plays a role in motor learning (riding a bike)
describe the functions of the brainstem
controls vital functions like breathing, heart rate, and blood pressure; basic functions like swallowing, digestion, and sleeping; serves as a pathway between the brain and spine
what are the 3 parts of the brainstem
medulla oblongata, pons, and midbrain
what are the functions of the medulla oblongata
controlling essential functions like breathing, heart rate, and blood pressure
what are the functions of the pons
involved in controlling breathing and regulating sleep; helps transmit signals
what are the functions of the midbrain
Handles sensory and motor functions, helping you see, hear, and move
Describe the reticular formation
LOCATION: like a network spread throughout the brainstem
FUNCTION: helps you stay awake, alert, and focused
list the cranial meninges
the tough dura mater, the fluid-filled arachnoid mater, and the delicate pia mater.
what is the function of the cranial meninges
They protect the brain from injury and cushion it from shocks, support the brain, supply it with nutrients, and regulate the flow of fluid around it
describe the ventricles of the brain
fluid filled spaces in the brain and generates CSF
what are the functions of the CSF
cushions the brain and spinal cord, removes waste, and delivers nutrients
how is CSF produced
by the choroid plexus in the brain, which filters blood and secretes CSF
how does CSF circulate within the CNS
the CSF circulates around and through the brain and spinal cord, going through the ventricles
how is the CSF absorbed into the bloodstream
Arachnoid granulations are specialized structures that act like one-way valves, allowing CSF to pass from the subarachnoid space into the bloodstream
describe the structure of the BBB
endothelial cells are tightly packed together to protect the brain; they are supported by astrocytes, which regulate the barrier
what is the importance of the BBB
it allows nutrients and glucose into the brain and keeps out toxins and pathogens
how does the endocrine and nervous system maintain homeostasis
the endocrine system uses hormones and works more slowly but has long-lasting effects, while the nervous system uses electrical signals for rapid communication and immediate responses to changes.
how does the hypothalamus maintain homeostasis
like the body’s manager; regulates body temperature, thirst, hunger, and sleep; adjusts hormone levels and nervous system activity
how does the reticullar formation of the medulla maintain homeostasis
it’s ready to act quickly; controls breathing, heart rate, and blood pressure;
where does thinking and decision making happen
the frontal love, especially the prefrontal cortex
where does understanding and producing speech happen
broca’s area for speeking, anf wernick’s are for understanding
Discuss the concept of cerebral lateralization
the concept that the left hemisphere is typically dominant for language and analytical tasks, while the right hemisphere is more involved in spatial awareness and creativity
what is short term memory
holds information temorarily (remembering a phone number for a short amount of time)
what is long term memory
it’s unlimited and you can remember it from months to an entire lifetime
what is sensory memory
holds info from your senses for a very short time in order to decide what is important
Describe the composition and function of the spinal cord
it’s filled with nerve fibers and surrounded by protective layers called meninges; carries messages to and from the brain, also plays a role and reflexes
describe dorsal horns
receive sensory signals from the body
describe ventral horns
describe lateral horns
They’re involved in controlling autonomic functions like heart rate, breathing, and digestion
describe ascending the descending tracts
ASCENDING: takes messages up to the brain
DESCENDING: takes messages down to the spinal cord
Explain the differences between the sensory and motor divisions of the peripheral nervous system
sensory (afferent) - carries messages from the senses to the brain
motor (efferent) - sends messages from your brain to the muscles and glands
what are the subdivisions of the sensory division
somatic sensory: send signals like touch and pain from skin and msucles
visceral sensory: sends signals like pressure and pain from internal organs
what are the subdivisions of the motor division
somatic motor: controls voluntary movements
visceral motor (autonomic): Regulates involuntary actions of organs
what are the subdivisions of the visceral motor division
sympathetic: the body’s fight or flight
parasympathetic: the body’s rest and digest
what are the 3 types of peripheral nerves
sensory, motor, and mixed nerves
what are spinal nerves
come from the spinal cord; control body movements and sensations; has 31 pairs
what are cranial nerves
come from the brain; control head, neck, and some internal organs; has 12 pairs
describe olifactory
(I)
sensory
sense of smell
describe optic
(II)
sensory
vision
describe oculomotor
(III)
motor
controls movements of muscles in the eye
describe trochlear
(IV)
motor
Controls the superior oblique muscle of the eye, which helps with downward and inward eye movements
describe trigeminal
(V)
mixed
transmit sensations from the face, scalp, and teeth to the brain, while motor fibers control the muscles involved in chewing
describe abducens
(VI)
motor
Controls the lateral rectus muscle of the eye, which moves the eye away from the nose
describe facial nerves
(VII)
mixed
Controls facial expressions, taste sensation from the anterior two-thirds of the tongue, and secretion of saliva and tears
describe Vestibulocochlear
(VIII)
sensory
-vestibular nerve: balance and spacial orientation
-cochlear: hearing
describe Glossopharyngeal
(IX)
mixed
sensory info from the tongue, throat, and parts of the ear; swallowing reflex and taste
describe vagus
(X)
mixed
transmitting sensory information from various organs in the chest and abdomen, controlling muscles involved in speech and swallowing, regulating heart rate and digestion, and influencing the function of many internal organs
describe accessory
(XI)
motor
head movement and shoulder elevation
describe hypoglossal
(XII)
motor
controls muscles in tongue
describe the anatomy of a spinal nerve
ROOTS: nerves start with two roots, dorsal (back) for feeling and ventral (front) for movement
NERVE: these roots join to form a single nerve
RAMI: spinal nerve splits into 2 branches, dorsal ramus for the back and ventral ramus for the rest of the body
PLEXUS: a network of nerves (like nerve hubs)
how many cervical nerve pairs are there
8
how many thoracic nerve pairs are there
12
how many lumbar nerve pairs are there
5
how many sacral nerve pairs are there
5
how many coccigeal nerve pairs are there
1
only once one takes the anatomy final, very good vacations are happening
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory. hypoglossal
List the four spinal
nerve plexuses
cervical, brachial, lumbar, and sacral plexus
Define sensory transduction
when your body processes tsenses it takes in into things you can understand
describe Exteroceptors by location and origin of stimuli
LOCATION: near the skin
STIMULI: senses things from outside of body like touch and temp
describe interoceptors by location and origin of stimuli
LOCATION: inside your body (organs)
STIMULI: hunger, thirst, blood pressure
describe proprioceptors by location and origin of stimuli
LOCATION: in muscles, tendons, and joints
STIMULI: monitor body position and movement
describe what mechanoreceptors detect and where
DETECT: pressure, vibration, stretch
WHERE: skin
describe what Thermoreceptors detect and where
DETECT: temperature
WHERE: skin and internal organs
describe what Chemoreceptors can detect and where
DETECT: chemical stimuli (taste, smell, changes in chemical composition of body)
WHERE: taste buds and nasal passages
describe what Photoreceptors can detect and where
DETECT: LIGHT STIMULI
WHERE: retina
describe what Nociceptors can detect and where
DETECT: painful stimuli
WHERE: distributed through body
whar are the 6 types of Mechanoreceptors
merkel cells, Meissner’s Corpuscles, Pacinian Corpuscles, Ruffini Endings, Hair Follicle Receptors, Free Nerve Endings
describe merkel cells
detect pressure and texture
describe meissner’s corpuscles
detects light touch and low frequency vibration
describe pacinian corpuscles
detect deep pressure and high frequency vibration
describe ruffini endings
detect skin stretch and continuous pressure
