Day 2.1 Flashcards
what are the functions of muscle?
- Movement
- Posture (skeletal muscles)
- Joint Stabilization (skeletal muscles)
- Thermogenesis – heat generation
- venous return
- energy source
- glycemic control
- contrl of openinfs and passageways
what does the skeletal muscle move?
skeleton
what does the cardiac muscle move?
blood
what does the smooth muscle move?
moves “stuff” through hollow organs
what muscle maintains posture?
skeletal muscles
what muscle maintains joint stabilization?
skeletal muscles?
what is the process of thermogenesis?
(heat generation)
Contracting skeletal muscles produce as much as 85% of our body heat
Working out
Shivering
what is the process of venous return in the muscle?
-Muscle pump action during dynamic exercise helps to pump/squeeze blood back to left ventricle
-This rhythmic pumping via contraction/relaxation increases venous blood return to the heart
how is the muscle a source of energy?
protein becomes an alternative source of energy during states of malnutrition or starvation
how the muscles perform glycemic control?
Muscles absorb and store glucose which helps regulate blood sugar concentration within normal range
how does muscles control the opening and passageways?
Sphincters: internal smooth muscle rings that control the movement of food, blood, and other materials within body
what are the classification of muscle function?
Action: effect produced by a muscle to produce or prevent movement
Four Functional Groups:
- Agonists (Prime movers)
Provide the major force for producing a specific movement - Antagonists
Oppose or reverse a particular movement - Synergists
muscle that aids the prime mover - Fixators
muscle that prevents movement of bone
Name the synergistic and anatagonistic muscle pairs
what is the origin site of attachment?
Point of muscle attachment on the immovable or less movable bone (in limbs, the origin is usually proximal to the insertion)
what is the insertion site of attachment?
Point of muscle attachment that moves toward the origin
what is the meaning of muscle innervation?
Innervation of a muscle — refers to the identity of the nerve that stimulates it
Knowing innervation enables diagnosis of nerve, spinal cord, and brainstem injuries from muscle tests
what is the muscle innervation of spinal nerves?
Spinal nerves arise from the spinal cord
Emerge through intervertebral foramina
Immediately branch into posterior and anterior rami
Innervate muscles below the neck
Plexus: web-like network of spinal nerves adjacent to the vertebral column
what is the muscle innervation of cranial nerves?
Cranial nerves arise from the base of the brain
Emerge through skull foramina
Innervate the muscles of the head and neck
Numbered CN I to CN XII
Name the structure of nerve-muscle functional unit
what is a motor unit?
a motor neuron and all the muscle fibers it innervates
what is the size principle?
Larger motor units are harder to activate, so a greater stimulus is needed to activate the larger motor units
Thus, smaller motor units always get activated first in any movement
what are the components of The Neuromuscular Junction (NMJ)?
- Axon terminal of a somatic motor neuron
- Synaptic Cleft
- Motor End Plate
what is the function of axon terminal?
Axon terminal of a somatic motor neuron
Releases the neurotransmitter acetylcholine (ACh)
what is the function of synaptic cleft?
Synaptic Cleft – microscopic space between motor end plate and axon terminal’s plasma membrane
what is the function of motor end plate?
Motor End Plate – depressed region of the sarcolemma with junctional folds present
Name the structures in the connective tissue of muscle
what are the types of muscle fibers in skeletal muscle?
Epimysium
Perimysium
Endomysium
what are characteristics of epimysium?
Epimysium
encircles the entire muscle
dense regular connective tissue
what are characteristics of perimysium?
Perimysium
surrounds groups of 10-100+ muscle fibers into bundles called fascicles
carries nerves, blood vessels, and stretch receptors
what are characteristics of endomysium?
Endomysium
surrounds individual myocytes
fine areolar connective tissue
Name the structures in skeletal muscle
what are the pyramid of subunits of skeletal muscle?
Name the skeletal muscle structure
Name the structures of the skeletal muscle
Name the skeletal fiber structure
what is myofibril?
contractile organelle that runs the length of the muscle cell
Name the structure of a skeletal muscle fibers
what are characteristics of sarcomere?
-Smallest contractile unit
-Region of a myofibril between two Z discs
-Composed of thick (myosin) and thin (actin) myofilaments
how many actin to myosin?
6 actin encircle each myosin thick filament
what are the myofilament proteins?
- Actin (contractile function)
- Myosin (contractile function)
- Troponin (regulatory function)
- Tropomyosin (regulatory function)
- Titan (structural function)
- Dystrophin (structural function)
what is actin?
Actin = thin contractile myofilament
what is myosin?
Myosin = thick contractile myofilament
what is the formation process of thin filament?
what is a crossbridge?
“head” portion of the myosin filament that “bridges” the gap between myosin and actin during contraction
Which is when Troponin & Tropomyosin relaxed vs contracted?
what are the steps of the excitation-contraction coupling process?
1 – A chemical (Ach) is released from a neuron, across the NMJ, and binds to receptors on the muscle fiber.
2 – This causes the muscle fiber to be electrically stimulated.
3 – This electrical stimulation travels down the T-tubule and triggers release of Ca+ from the SR.
4 – Ca+ bonds to troponin, moving tropomyosin, exposing myosin binding sites on actin
5 - Contraction begins
6 – Ca+ quickly starts to return to the SR
7 – As Ca+ levels drop tropomyosin “covers-up” actin, preventing further contraction
what is involved with muscle force production?
- The cross-bridge cycle
- the sliding filament theory
explain the cross-bridge cycle
Cycle of events that explains how a single myosin protein undergoes movement
explain the sliding filament theory
Theory which explains how, by virtue of all mysoins undergoing the “cross-bridge cycle” the whole sarcomere can shorten in length
what happens in the cross-bridge cycle when Ca+ is present?
When Ca+ is present:
1 – Myosin-binds-actin, creating a cross-bridge.
2 – The head of myosin “snaps”, pulling the actin toward the m-line of the sarcomere
Now ATP is need to:
3 – Detachment of myosin from actin.
4 – Mysoin is “re-cocked” into high energy state using the energy from ATP hydrolysis (breakdown).
Thus, Ca+ and ATP needed for muscle contraction!
which states are in the 3D arrangement of the sarcomere?
Name the structure in the sliding filament mechanism of contraction
What are the subdivisions of the nervous system?
CNS
PNS
types of neurons?
Multipolar neuron
Bipolar neuron
Unipolar neuron
Anaxonic neuron
what are characteristics of multipolar neuron?
Multipolar neuron
One axon and multiple dendrites
Most common – most neurons in CNS
what are characteristics of bipolar neuron?
Bipolar neuron
One axon and one dendrite
Olfactory cells, retina, inner ear
what are the characteristics of unipolar?
Unipolar neuron
Single process leading away from neurosoma
Sensory cells from skin and organs to spinal cord
what are characteristics of anaxonic neuron?
Anaxonic neuron
Many dendrites but no axon
Retina, brain, and adrenal gland
Name the neuroglial cells of CNS
what are the types of glial cells in the CNS
Oligodendrocytes
Ependymal cells
Microglia
Astrocytes
what are characteristics of oligodendrocytes?
Oligodendrocytes
Form myelin sheaths in CNS that speed signal conduction
what are characteristics of ependymal cells?
Ependymal cells
Line internal cavities of the brain; secrete and circulate cerebrospinal fluid (CSF)
what are characteristics of microglia cell?
Microglia
Wander through CNS looking for debris and damage (protective)
what are characteristics of astrocyte cells?
Astrocytes
Most abundant glial cell in CNS, covering brain surface and most nonsynaptic regions of neurons in the gray matter, serving many diverse functions
what are the types of cells in PNS only?
Schwann cells
Satellite cells
what are characteristics of Schwann cells?
Schwann cells
Envelope nerve fibers in PNS
Wind repeatedly around a nerve fiber
Produce a myelin sheath similar to the ones produced by oligodendrocytes in CNS
Assist in regeneration of damaged fibers
what are the characteristics of satellite cells?
Satellite cells
Surround the neurosomas in ganglia of the PNS
Provide electrical insulation around the neurosoma
Regulate the chemical environment of the neurons
what factors does speed of nerve impuse depend on?
- Diameter of fiber
Larger fibers have more surface area and conduct signals more rapidly - Presence or absence of myelin
Myelin further speeds signal conduction
Ranking slowest to fastest fibers
Slowest to fastest:
Small, unmyelinated fibers: 0.5 to 2.0 m/s
Small, myelinated fibers: 3 to 15.0 m/s
Large, myelinated fibers: up to 120 m/s
Slow signals sent to the gastrointestinal tract where speed is less of an issue
Fast signals sent to skeletal muscles where speed improves balance and coordinated body movement
what is an electrical potential?
A difference in concentration of charged particles between one point and another
what is the resting membrane potential?
-70mV
what characteristics of the electric potential?
-Living cells are polarized and have a resting membrane potential
-Cells have more negative particles on inside of membrane than outside
-Neurons have about −70 mV resting membrane potential
what is the electrical current?
A flow of charged particles from one point to another
what ions are moved through the plasma membrane?
Na+ or K+
How are gated channels opened or closed?
-Gated channels are opened or closed by various stimuli
-Enables cell to turn electrical currents on and off
Why does the resting membrane potential occur?
The resting membrane potential is due to a small buildup of negatively charged ions, mainly organic phosphates (PO43−) and proteins, in the cytosol just inside the membrane and an equal buildup of positively charged ions, mainly sodium ions (Na+), in the interstitial fluid just outside the membrane
what is the ratio of Na+ to K+ moving?
Na^+/ K^+ pump moves 3 Na^+ out for every 2 K^+ it brings in
Maintains RMP
Works continuously to compensate for Na^+ and K^+ leakage, and requires great deal of ATP (1 ATP per exchange)
At rest, what is the plasma membrane?
POLARIZED at rest… there is a difference in potential across the membrane
Describe the changes in membrane potential
what are ligand?
(chemicals that bind to a receptor) can bind and cause opening of certain ion channels in the plasma membrane. This allows ions to travel into (or out) of the cell, changing the membrane potential. This change is termed a local (or graded) potential.
What occurs when excitation of a neuron by a chemical stimulus?
Ligand-gated ion channels
The ion channels will open when a specific ligand binds to the receptor connected to the channel
what is an action potential?
A dramatic change in membrane polarity produced by voltage-gated ion channels
where is the abudance of voltage-gated ion channels?
axon hillock
what is the threshold stimulus?
55 mV
what occurs when If the stimulus makes the conditions at the axon hillock reach the threshold stimulus of -55mV?
then an ACTION POTENTIAL will travel down the whole length of the axon!
what are the steps of an action potential?
steps of the sodium and potassium channel during action potential
- Na^+ and K^+ channels closed
- Na^+ channels open, Na^+ enters cell, K^+ channels beginning to open
- Na^+ channels closed, K^+ channels fully open, K^+ leaves cell
- Na^+ channels closed, K^+ channels closing
what is the threshold: all or none principle?
unless threshold is achieved then nothing occurs
what are the absolute and relative refractory periods?
During an action potential and for a few milliseconds after, it is difficult or impossible to stimulate that region of a neuron again
what is continous conduction?
-Chain reaction continues until the nerve signal reaches the end of the axon
-The nerve signal is like a wave of falling dominoes
how do myelinated fibers conduct signals?
-Myelinated fibers conduct signals with saltatory conduction
-Nodes of Ranvier contain many voltage-gated ion channels, while myelin-covered internodes contain few
conduction in myelinated fiber during refractory periods
Refractory periods ensure the action potential continues in the correct direct, away from the axon hillock towards the axon terminals.
what are the steps of synaptic transmission?
- nerve impusle
- Ca+ move through the voltage gated Ca+ Channels
- the synaptic vesicles move out of cell
- Na+ move out of the ion channels
- the ion channels open and move it
- depolarization
- nerve impulse
what is a neurotransmitter?
-molecules that are released when a signal reaches a synaptic knob that binds to a receptor on another cell and alter that cell’s physiology
-More than 100 neurotransmitters have been identified but most fall into four major chemical categories:
what are the major chemical categories?
- Acetylcholine
- Amino acid
- monoamines
- neuropeptides
how is the spinal cord divided?
Spinal cord divided into the:
Cervical region
Thoracic region
Lumbar region
Sacral region
where is the spinal cord thicker than elsewhere?
-Cervical enlargement: nerves to upper limb
-Lumbar enlargement: nerves to pelvic region and lower limbs
what is the medullary cone (conus medullaris)?
Medullary cone (conus medullaris):
cord tapers to a point inferior to lumbar enlargement
what is the Cauda equina?
Cauda equina:
bundle of nerve roots that occupy vertebral canal from L2 to S5
Name the structures in the meninges of the spinal cord
Name the structures of the meninges of the spinal cord
what is the composition of CSF?
-Watery solution
-Less protein & different ion concentrations than plasma
-Constant volume
what are the functions of CSF?
Gives buoyancy to the CNS organs
Protects the CNS from blows and other trauma
Nourishes the brain and carries chemical signals
what is gray matter?
neuron cell bodies with little myelin
what roles does gray matetr play in the spinal cord anatomy?
-shaped like a butterfly
-site of information processing, synaptic integration
what is white matter?
abundantly myelinated axons (tracts)
what role does white matter play in the spinal cord anatomy?
-three columns
-carries signals from one part of the CNS to another
what is the function of the ascending tract?
carry sensory signals up the spinal cord
what is the function of the descending tract?
carry motor signals down brainstem and spinal cord
The ascending tract involved what neurons for sensory signaling?
-First-order neurons: detect stimulus and transmit signal to spinal cord or brainstem
-Second-order neurons: continues to the thalamus at the upper end of the brainstem
-Third-order neurons: carries the signal the rest of the way to the sensory region of the cerebral cortex
what is the function of the first order neuron?
First-order neurons: detect stimulus and transmit signal to spinal cord or brainstem
what is the function of the second order neuron?
Second-order neurons: continues to the thalamus at the upper end of the brainstem
what is the function of the third order neuron?
Third-order neurons: carries the signal the rest of the way to the sensory region of the cerebral cortex
The descending tract involves what neurons for carrying motor signals?
Upper motor neuron originates in cerebral cortex or brainstem and terminates on a lower motor neuron
Lower motor neuron neurosoma is in brainstem or spinal cord
Axon of lower motor neuron leads to muscle or other target organ
what is the function of the upper motor neuron?
Upper motor neuron originates in cerebral cortex or brainstem and terminates on a lower motor neuron
what is the function of the lower motor neuron?
-Lower motor neuron neurosoma is in brainstem or spinal cord
+Axon of lower motor neuron leads to muscle or other target organ
what is the function of the spinal cord?
Spinal cord communicates with the rest of the body by way of spinal nerves
what is the function of the nerve?
Nerve: a cord-like organ composed of numerous nerve fibers (axons) bound together by connective tissue
Name the structures of the nerve anatomy
Name the structure of the horns and roots
what are the branched nerve plexuses? 5
- Cervical plexus in the neck, C1 to C5
- Brachial plexus near the shoulder, C5 to T1
- Lumbar plexus in the lower back, L1 to L4
- Sacral plexus in the pelvis, L4, L5, and S1 to S4
- Coccygeal plexus, S4, S5, and Co1
What is the somatosensory function?
carry sensory signals from bones, joints, muscles, and skin
what is the motor function?
primarily to stimulate muscle contraction
Name the nerve plexus
Name the nerve and root of the cervical plexus
what is the function of the brachial plexus?
Supply/receive from the muscles and skin of the arm
name the cords and nerve of the brachial plexus
what is the function of the lumbar plexus?
Supply/receive from the muscles of the abdomen and thigh
Name the structures of the lumbar plexus
Name the structures of the sacral and coccygeal plexuses
what is the function of the sacral and coccygeal plexuses
Supply/receive from the buttock, lower limb, pelvic structures
what occurs with complete transection?
-complete severence of cord
-Immediate loss of motor control below level of injury
-Above C4 poses the threat of respiratory failure
-Spinal shock (hypotension)
-Paralysis (loss of motor and sometimes also sensory function):
what is complete transection?
severance of cord
what is paraplegia?
Paraplegia: paralysis of both lower limbs
what is quadriplegia?
Quadriplegia: paralysis of all four limbs
what is hemiplegia?
Hemiplegia: paralysis on one side of the body
what is paresis?
Paresis: partial paralysis or weakness of the limbs
what is a dermatone?
a specific area of skin that conveys sensory input to a spinal nerve
what is a dermatomes map?
a diagram of the cutaneous regions innervated by each spinal nerve
how much does dermatomes overlap?
-Dermatomes overlap their edges as much as 50%
-Necessary to anesthetize three successive spinal nerves to produce a total loss of sensation in one dermatome
what is the steps of a representative reflex arc?
- receptor in muscle near tendon
- afferent (sensory nerve fiber send to sensory neurons
- synapse in spinal integrating center
- efferent (motor) nerve fiber
- effector (quadriceps femoris muscle)
where are stretch receptors embedded?
Stretch receptors embedded in skeletal muscles
Proprioceptor - specialized sense organs to monitor position and movement of body parts
what is the function of muscle spindles?
Muscle spindles inform the brain of muscle length and body movement
Enables brain to send motor commands back to the muscles that control coordinated movement, corrective reflexes, muscle tone, and posture
what steps of patellar tendon reflex?
-monosynaptic stretch reflex
1. Tap on patellar ligament excites nerve endings of muscle spindle in quadriceps femoris.
2. Stretch signals travel to spinal cord via primary afferent fiber and dorsal root.
3. Primary afferent neuron stimulates alpha motor neuron in spinal cord.
4. Efferent signals in alpha motor nerve fiber stimulate quadriceps to contract, producing knee jerk.
5. At same time, a branch of the afferent nerve fiber stimulates inhibitory motor neuron in spinal cord.
6. That neuron inhibits alpha motor neuron that supplies hamstring muscles.
7. Hamstring contraction is inhibited so hamstrings (knee flexors) do not antagonize quadriceps (knee extensor).
what are the steps for the Flexor and Crossed Extension Reflexes?
- Stepping on glass stimulates pain receptors in right foot
- Sensory neuron activates multiple interneurons
- Ipsilateral motor neurons to flexor excited
- Ipsilateral flexor contracts
- Contralateral motor neurons to extensor excited
- Contralateral extensor contracts
what is tendon reflex?
Tendon reflex: in response to excessive tension on the tendon
Inhibits muscle from contracting strongly
Moderates muscle contraction before it tears a tendon or pulls it loose from the muscle or bone
where are proprioceptors located?
Tendon organs: proprioceptors in a tendon near its junction with a muscle
Golgi tendon organ: 1 mm long, nerve fibers entwined in collagen fibers of the tendon
what are the regions of the brain?
Cerebral Hemispheres
Diencephalon
Brainstem
Cerebellum
Name the regions in the brain
Ridges (gyrus), shallow grooves (sulcus), and deep grooves (fissures), ventricles (spaces)
what are the lobes of the cerebral hemispheres?
Frontal
Parietal
Temporal
Occipital
Insula
Name the structures of the surface anatomy of the brain
Name the structures of the lateral aspect of the brain
Name the structures of the medial aspect of the brain
what does the cerebral cortex consist of?
-Superficial layer of gray matter
-white matter beneath
-40% of the mass of the brain
what is the function of the cerebral cortex?
-Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
-Each hemisphere connects to contralateral side of the body
what are the meninges?
Meninges: three connective tissue membranes that envelop the brain
what the connective tissues that make up meninges?
- dura mater
- arachnoid mater
- pia mater
Name the structures of the meninges
Name the ventricles and associated structures for CSF
what is the step process of the flow of CSF
- CSF is secreted by choroid plexus in each lateral ventricle
- CSF flows through interventricular foramina into third ventricle
- choroid plexus in third ventricles adds more CSF
- CSF flows down cerebral aqueduct to fourth ventricle
- choroid plexus in fourth ventricle adds more CSF
- CSF flows out two lateral apertures and one median aperture
- CSF fills subarachnoid space and bathes external surfaces of brain and spinal cord
- At arachnoid villi, CSF is reabsorbed into venous blood of dural venous sinuses
Name the structures in the process of CSF
Name the Hindbrain and Midbrain
Name the structures of the cerebellum
what does the diencephalon contain
Thalamus
Hypothalamus
Epithalamus
Name the diencephalon structures
Name the lobes of the cerebrum and their key functions
what are higher brain functions?
-Functions of brain do not have easily defined anatomical boundaries:
-Involve interactions between cerebral cortex, basal nuclei, brainstem, and cerebellum
-Integrative functions focus mainly on cerebrum, but involve combined action of multiple brain levels
Label which gyrus and cortex
The Primary Somatosensory Cortex (Postcentral Gyrus)
Label which gyrus and cortex
Primary Motor Cortex (Precentral Gyrus)
Label the language centers of the left hemisphere
Label the lateralization of cerebral functions
what are characteristices of the cranial nerves
-12 Pairs
-Most are mixed in function
-Connect brain to structures of head and neck
exception is Vagus nerve (X)
-Most cranial nerves carry fibers between brainstem and ipsilateral receptors and effectors
what are the functions of the cranial nerves?
- olfactory nerve- smell
- optic nerve-vision
- oculomotor nerve-move eyeballs
- trochlear nerve-move eyeballs
- trigeminal nerve-facial sensations, chewing
- abducens nerve-move eyeballs
- facial nerve-facial expressions, taste
- vestibulocochlear nerve-hearing and balance
- glossopharyngeal nerve-muscle movement, taste
- vagus nerve-parasympathetic effects
- accessory nerve-neck muscle movement
- hypoglossal nerve-tongue movement
what is the function the autonomic nervous system (ANS)?
-Autonomic Nervous System (ANS) is independent of our will
-ANS regulates fundamental states and life processes such as heart rate, BP, and body temperature
-Also called visceral motor system
-Walter Cannon coined the terms “homeostasis” and the “flight-or-fight”
Animals without ANS cannot survive on their own (must be kept warm and stress-free)
what are the steps of the example baroreflex?
- Baroreceptors sense increased blood pressure
- Glossopharyngeal nerve transmits signals to medulla oblongata
- Vagus nerve transmits inhibitory signals to cardiac pacemaker
- Heart rate decreases
Can the different divisons of thje ANS work together?
Two divisions often innervate same target organ
May have cooperative or contrasting effects
what are the functions of the sympathetic division?
Sympathetic division
Prepares body for physical activity: exercise, trauma, arousal, competition, anger, or fear
Increases heart rate, BP, airflow, blood glucose levels, etc.
Reduces blood flow to the skin and digestive tract
“Fight-or-flight”
what are the functions of the parasympathetic division?
Parasympathetic division
Calms many body functions reducing energy expenditure and assists in bodily maintenance
Digestion and waste elimination
“Resting and digesting”
what are Comparisons of Somatic vs Autonomic Efferent Pathways?
Direct synapse
vs
short preganglionic, long postganglionic
vs
Long preganglionic, short postganglionic
what are the autonomic effects on target organs, parasympathetic vs sympathetic
what information does sensory receptors transmit?
- Modality – type of stimulus or sensation it produces
e.g. vision, hearing, taste - Location – encoded by which nerve fibers are firing
Receptive field: area within which a sensory neuron detects stimuli - Intensity – strength of stimulus
Brain can distinguish stimulus intensity by:
Which fibers are sending signals
How many fibers are doing so
How fast these fibers are firing - Duration — how long the stimulus lasts
Sensory adaptation: if a stimulus is prolonged, firing of the neuron gets slower over time
What ways to classify receptors?
- By receptor modality
- By receptor location
- By receptor complexity
what are the receptors classified by modality?
-Mechanoreceptors
respond to touch, pressure, vibration, stretch, and itch
-Thermoreceptors
sensitive to changes in temperature
-Photoreceptors
respond to light energy (retina)
-Chemoreceptors
respond to chemicals (smell, taste, changes in blood chemistry)
-Nociceptors
sensitive to pain-causing stimuli
what receptors are classfied by location?
-Exteroceptors
Respond to stimuli arising outside the body
Receptors in the skin for touch, pressure, pain, and temperature
Most special sense organs
-Interoceptors (visceroreceptors)
Respond to stimuli arising inside the body
-Proprioceptors
Stretch receptors in muscles, tendons, ligaments, joints and connective tissues
what receptors are classfied by structural complexity?
- Complex receptors
Special sense organs
Vision, hearing, equilibrium, smell, and taste - Simple receptors
For general senses
Tactile sensations (touch, pressure, stretch, vibration), temperature, pain, and muscle sense
Unencapsulated (free/naked)
Encapsulated dendritic endings
what are receptors for general senses?
Free nerve endings
tactile disc
hair receptos
tactile corpuscle
end bulb
bulbous corpuscle
lamellar corpuscle
muscle spindle
tendon organ
what are unencapsulated nerve endings?
Unencapsulated nerve endings lack connective tissue wrappings
what receptors are unencapsulated nerve endings
-Free nerve endings
For pain and temperature
Skin and mucous membrane
-Tactile discs
For light touch and texture
Associated with Merkel cells at base of epidermis
-Hair receptors
Coil around a hair follicle
Monitor movement of hair
what receptors are Encapsulated Nerve Endings
-Tactile corpuscles
Light touch and texture
Dermal papillae of hairless skin
-Krause end bulbs
Tactile; in mucous membranes
-Bulbous corpuscles (tonic)
Heavy touch, pressure, joint movements, and skin stretching
-Lamellar corpuscles (phasic)
Deep pressure, stretch, tickle, and vibration
Periosteum of bone, and deep dermis of skin
what are encapsulated nerve endings?
Encapsulated nerve endings are wrapped by glial cells or connective tissue. Wrapping enhances sensitivity or selectivity of response.
what are included in chemical senses?
Gustation – taste
Olfaction – smell
Name the structures in the gustatory (taste) receptors
what is the phsyioplogy of taste?
To be tasted, molecules must dissolve in saliva and flood the taste pore
Five primary sensations:
Salty
Sweet
Umami (“meaty” taste)
Sour
Bitter
what is the process of taste?
- Taste buds
- Facial nerve
Glossopharyngeal nerve
Vagus nerve - Hypothalamus and amygdala Postcentral gyrus
Integrated with signals from nose and eyes
what are the only neurons in the body that directly exposed to the external environment?
Olfactory Receptors
Name the structures of the olfactory receptors
what is the olafactory receptors histology?
Basal cells: Divide and differentiate to replace olfactory cells
what is the olafactory projection pathway?
- Action potentials reach primary olfactory cortex in the inferior surface of the temporal lobe
2/ Secondary destinations: hippocampus, amygdala, hypothalamus, insula, and orbitofrontal cortex
Identify odors, integrate with taste, evoke memories, emotions, and visceral reactions
what is hearing?
a response to vibrating air molecules
Both senses reside in the inner ear, a maze of fluid-filled passages and sensory cells
Fluid is set in motion and the sensory cells convert this motion into an informative pattern of action potentials
what is equilibrium?
the sense of motion, body orientation, and balance
Both senses reside in the inner ear, a maze of fluid-filled passages and sensory cells
Fluid is set in motion and the sensory cells convert this motion into an informative pattern of action potentials
Label the anatomy of the inner ear
what is the difference between auditory tube in adult vs infant
what is the bony labyrinth?
passageways in temporal bone
what is thye membranous labyrinth?
fleshy tubes lining bony labyrinth
Filled with endolymph: similar to intracellular fluid
Floating in perilymph: similar to cerebrospinal fluid
what is the labyrinth?
vestibule and three semicircular ducts (equilibrium receptors)
what is the cochlea?
organ of hearing
Name the structures of the inner ear
Label the anatomy of the cochlea
Label the anatomy of the eye
Label the optical components
Label the optical components (part 2)
