Midterm 2 Flashcards
What do the alveolar macrophages do?
they ingest debris in alveoli and become trapped in the mucus sheets
What do the type II alveolar cells do?
they secrete surfactant which lowers the surface tension of alveolar fluid to inflate the alveoli and prevent alveolar walls from sticking together and collapsing
What are type II alveolar cells?
they are a kind of stem cell that is able to regenerate more of itself and type I
Where is the respiratory epithelium found?
nasal cavity, nasopharynx, and the large airways
What is the respiratory epithelium?
a pseudostratified epithelium that has a mucus layer that floats on a serious (watery) layer
What are the causes for emphysema?
smoking and other irritants like pollution or dust
What is emphysema?
the breakdown of alveolar walls producing abnormally large air spaces and lowering the surface area for gas exchange ( reduced respiratory efficiency) and reducing the elastic recoil ( due to loss of elastic fibers)
What happens during an asthma attack?
the bronchioles are affected and inflamed and become susceptible to contraction by mediator histamine which causes the contraction of smooth muscle
What is the function of the elastic fibers in the airway wall?
they predominate in smaller airways and the respiratory portion. Their elastic recoil provides force for expiration
What is the function of the smooth muscle in the airway wall?
it predominates in smaller airways and controls the diameter of the airway. The constriction of it reduces airflow
What is the function of cartilage in the airway wall?
it is found in larger airways and helps keep them open
What is the funciton of the respiratory airway?
both to conduct air and respire
What structures are apart of the respiratory airway?
located entirely within the lung and are represented by respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
What is the function of the conducting airway?
to warm, moisten and conduct air
What structures are included in the conducting airway?
the nose, pharynx, larynx, trachea, bronchi, and bronchioles
What are the 2 types of airways?
conducting and respiratory
What is the function of the alveoli?
to minimize amount of tissues but maximize air space
What is the respiratory bronchioles?
they are the start of the respiratory airway, and they terminate on alveolar ducts
What is the function of the terminal bronchiole?
to move air in and out, it is the last conducting airway
Cartilage ring shape of the trachea?
C-shaped not O-ring shaped
The amount of cartilage in bronchioles and bronchi ?
bronchi- little cartilage
bronchioles- no cartilage but supported by smooth muscle
What is the root (Hilum) of the lung?
the site where blood vessels, lymphatics, nerves, and airways enter and leave lungs
What happens when you swallow?
when passing food any connection between the breathing and GI tract must be cut off so the tongue will push the soft palate up and back closing the nasopharynx. The epiglottis is also closed by bringing the larynx up
What are turbinates? (nasal conchae)
bony shelves covered in a mucous membrane that force air close to the warm wall (narrow channels)
What is the epiglottis composed of?
cartilage
What does the eustachian tube do?
it connects the middle ear to the nasopharynx to equalize pressure
What is the nasopharynx composed of?
lots of lymphoid tissue
What is the respiratory portion of the respiratory system?
where gas exchange happens (alveoli)
What is the conduction portion of the respiratory system?
the portion that takes in air
What are the functions of the respiratory system?
exchange of gas between the atmosphere and the blood. Filtration, temperature regulation, and humidification of inspired air (the air we breathe in)e
What happens if the CN XII is damaged?
inability to protrude tongue symmetrically (stick out tongue)
What is the CN XII-hypoglossal nerve attached to?
the medulla
What is the function of the CN XII- Hypoglossal nerve?
it is a pure motor nerve that supplies muscles of tongue and enables tongue movement
What happens if the CN XI is damaged?
weakness when shrugging (elevating) shoulders, turning head to one side against resistance
What is the function of the CN XI- Spinal accessory nerve?
it only has a motor function that supplies trapezius and sternocleidomastoid muscles in the neck
What is the function of the vagus nerve- CN X?
it is a mixed nerve responsible for the regulation of internal organ functions, such as digestion, heart rate, and respiratory rate, as well as vasomotor activity, and certain reflex actions, such as coughing, sneezing, swallowing, and vomiting
What happens if there is damage or disease to the CN IX- Glossopharyngeal nerve?
difficulty in swallowing, loss of gag reflex
What is the CN IX- Glossopharyngeal nerve attached to?
the medulla
What is the primary function of the CN IX- Glossopharyngeal nerve?
mixed (sensory and motor), it is located at the back of the tongue so it controls gag reflex
What happens if there is damage/disease to the cochlear part of the CN VIII?
difficulty in localizing sound
What happens if there is a disease in the vestibular apparatus of the CN VIII?
Meniere’s syndrome (vertigo, nausea, vomiting)
What are the primary functions of CN VIII- vestibulocochlear nerves?
special sensory: balance and equilibrium (vestibular division) and hearing (cochlear division)
What are the parasympathetic functions of CN VII?
controlling the lacrimal gland for tearing (lacrimation) via pterygopalatine ganglion (V2) and submandibular salivary glands via submandibular ganglion (V3)
What are the sensory functions of the CN VII?
control taste to anterior 2/3 of tongue (via chorda tympani) and some sensory goes to skin around ear
What are the motor functions of the CN VII?
control the muscles of facial expression (5 sets of branches)
What happens if the CN VII- facial nerve is damaged?
patient may lose taste (partly), salivation (partly) or lacrimation in one eye, or also get Bell’s Palsy where half of the face is paralyzed
What are the functions of CN VII- Facial nerve?
both sensory and motor (mixed): controls taste, not chewing however, cheeks and lips, muscle to neck, and lacrimation (keeping eyes moist)
What happens if the CN VI- Abducent nerve is damaged?
it leads to paralysis of lateral rectus which ultimately leads to double vision (diplopia), the abducent nerve in general is vulnerable to injury in head trauma or raised intracranial pressure
Where is the CN VI- Abducent nerve located?
at ponto-medullary (between pons and medulla) junction
What is the one muscle that the CN VI- Abducent Nerve supply?
lateral rectus (abducts the eye–> ABducent nerve)
What are the sensory functions of the CN V3- Mandibular nerve?
sensation of lower lip and lower teeth, chin and tongue
What are the motor functions of the CN V3 Mandibular nerve?
supplies muscles of mastication (controlling force of bite)
What is the function of the CN V2- Maxilary Nerve?
it is a pure sensory that supplies sensation to the maxillary air sinus, nasal cavity, lower eyelid, skin of the cheek, maxillary (upper) teeth, and gums
What is the function of the CN V1- Ophthalmic nerve?
it is a pure sensory that supplies sensation to the frontal and ethmoidal paranasal air sinuses, the upper eyelid, side of the nose, forehead, and scalp
What are the largest cranial nerves?
trigeminal nerves (V)
What happens if there is a disease in the CN V- trigeminal nerve?
Tic Douloureux (mainly in V2 and V3), “suicide disease” because of the chronic pain by sensory axons firing inappropriately
What are the 3 divisions (branches) arising from trigeminal ganglion in CN V?
V1- Ophthalmic nerve: sensation of forehead and eye e.g. putting on contacts (pure sensory)
V2- Maxillary nerve: cheek (pure sensory)
V3- Mandibular nerve: mandible (motor and sensory- because it can deal with physically chewing and pain of the lower teeth)
What is the only cranial nerve to emerge from back of brainstem?
trochlear nerve - CN IV
What is the one muscle that the trochlear nerve CN IV supply?
superior oblique
What is the smallest cranial nerve?
CN IV- Trochelar Nerve
What are the primary functions of the CN III- Oculomotor nerve?
motor and eye movements
What happens if the CN III- Oculomotor Nerve is damaged/ disease?
pupillary dilation (will not be able to constrict pupil) and ophthalmoplegia (eye movements are weakened or paralysed)
What does the levator palpebrae superioris do?
elevate the upper eyelid
What are the 2 extra-ocular muscles that CN III- Oculomotor nerve does NOT innervate?
LR6 SO4
the lateral rectus (responsibility of CN VI) and superior oblique (responsibility of CN IV)
Where in the eye does the oculomotor nerve (CN III) supply?
the superior rectus, medial rectus, inferior oblique, inferior rectus and levator palpebrae superioris
What is the path that the optic nerve travels down starting at the retina?
1) Pass through the optic canals of the sphenoid before forming the optic chiasm (chiasma= crossing– because it looks like a X)
2) Axons continue to lateral geniculate nucleus (LGN) of the thalamus as the optic tracts
3) they synapse at the thalamus (LGN) where projection fibers will then end in the occipital lobe
Where does the optic nerve (CN II) originate?
retina
What is the primary function of CN II- Optic nerves?
special sensory (vision)
What happens if the CNII - Optic Nerve is damaged or disease?
there will be visual field defects
What is the optic nerve comprised of?
several axons
The path that olfactory nerves (CN I) travels, starting at the specialized neurons in the epithelium covering the roof of the nasal cavity
1) sensory neurons collect to form bundles
2) these bundles enter the olfactory bulbs
3) the axons along the olfactory tracts carry signal to cerebrum
What is the primary function of olfactory nerves (I)?
special sensory (smell)
What happens when the CN I - Olfactory nerve is damaged/ disease?
hyposmia (low smelling) and/or anosmia (no smelling)
Which cranial nerves have to do with eye movements?
III, IV, VI
Which cranial nerve does any sensation of the face travel through?
V - Trigeminal
What are the names of the 12 cranial nerves with corresponding roman numerals?
I- Olfactory II- Optic III- Oculomotor IV- Trochlear V- Trigeminal VI- Abducens VII- Facial VIII- Audiovestibular IX- Glossopharyngeal X- Vagus XI- Spinal Accessory XII- Hypoglossal
What does a pure motor nerve mean?
it goes straight to skeletal/voluntary muscle
What functions do most cranial nerves except CN X run?
functions of the head and neck
Spinal vs Cranial nerves?
spinal nerves emerge from the spinal cord and cranial nerves emerge from the area of the brain stem
What is referred pain?
pain in a visceral (internal) organ that is conveyed onto brain and makes you feel like there is pain on the skin (because brain does not know about viscera)
What is direct (somatic) pain?
a sharp, well-focused and easily localized pain that arises from the skin of body walls and limbs
What is the nerve plexus?
the area that spinal nerves connect with other spinal nerves
What are the somatic nerve plexuses?
brachial plexus, lumbar plexus, lumbosacral plexus
What are dermatomes?
strip of skin innervated by one spinal nerve, no overlap of spinal nerves
What are visceral efferents?
autonomic fibers innervating smooth muscle, cardiac muscle and glands
What are somatic efferents?
motor neurons in ventral horn projecting to skeletal muscles
What are visceral afferents responsible for?
pain, distension, chemical from visceral structures
What are somatic afferents responsible for ?
pain, temperature, touch, proprioception from body wall
What are the 2 general efferents?
somatic and visceral
What are the 2 general afferents?
somatic afferents and visceral afferents
What are the 31 pairs of spinal nerves?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Where do spinal nerves emerge from?
the spinal cord
Where do cranial nerves emerge from?
the brain stem
What is CNS responsible for?
integrates, processes and coordinates sensory data and motor command
What is PNS responsible for?
carries sensory information from receptors to CNS (afferent division), and carries motor commands from the CNS to periphery (efferent division)
Where are the cell bodies located in the CNS?
in the nuclei
Where are axons located in the CNS?
in tracts
Where are the cell bodies located in the PNS?
ganglia
Where are axons located in the PNS?
in the nerves
What are nuclei?
a cluster of neurons together
What are neurons?
nerve cells that conduct signals
What are neuroglia?
support cells for the neurons
How do neurons form connections with other cells?
via synapses
What does the cell body of a neuron contain?
the nucleus, mitochondria and ribosomes etc.
What do axons do?
conducts nerve impulses (action potential) toward synaptic terminals
What stimulates dendrites?
environmental changes or the activities of other cells
What is a synapse?
point of contact of an axon terminal with another cell, transmits nerve impulse via neurotransmitter
What are the PNS neuroglia?
Schwann cells and satellite glial cells
What are the CNS neuroglia?
astrocytes, oligodendrocytes, microglia and ependymal cells
What are satellite cells?
cells that surround sensory neuronal cell body and have a supportive role (regulate neurotransmitter O2, CO2)
What are the functions of Schwann cells?
to myelinate peripheral axons (sensory and motor)
What are the functions of oligodendrocytes?
to myelinate CNS axons; provide structural framework
What are the functions of the microglia?
to remove cell debris, wastes, and pathogens by phagocytosis
What are the functions of astrocytes?
to maintain the blood-brain barrier by “hugging/wrapping” around the barriers
What are the functions of the ependymal cells?
line ventricles (brain) and central canal (spinal cavity); assist in producing, circulating and monitoring of CSF
What are the functions of meninges?
to cover and protect the CNS
Different mater that are part of meninges?
Dura mater, Arachnoid Mater and Pia Mater
What does the CNS float in?
cerebrospinal fluid
Why does brain look wrinkled?
because of the sulcus and gyrus, which increases surface area by wrinkling
Functions of the cerebrum?
higher cognitive functions (thought, intellect, planning and creativity), language and speech (formulation and comprehension), somatic motor function (regulates skeletal muscle activity and regulates movement), somatic sensory function (interpret stimuli from environment) and regulates the emotional aspects of behavior
What is housed in the outer gray matter?
the cell bodies
What can be found in the white matter?
the axons
Why is the white matter (medulla) called that?
it looks white because of the myelinated axons it has
What are the 3 fiber tracts in the brain?
association fibres, commissural fibres and projection fibres
What do the association fibres do?
they stay within one hemisphere and have intrahemispheric connections which can be either short or long
What do commissural fibres do?
are interhemispheric connections (go from one hemisphere to another)
What do projection fibres do?
travel to and from the cortex (will leave the cortex to go to the spinal cord)
What does the cerebellum do?
it acts as a comparator (comparing intended movement with evolving movements and corrects for errors) ensuring that movements are smooth, coordinated and purposeful e.g. baby trying to walk
What disease can be a result of damage to the cerebellum?
cerebellar ataxia (intention tremor- when you are moving too many muscles are being told to move at the same time)
What are the 3 parts of the brainstem?
the midbrain, pons and medulla
What are the functions of the brainstem?
it is a house for cranial nerves (origin), it contains a reticular activating system that is important for arousal of cortex and consciousness, and has vital centres for regulating heart rate, swallowing, gag reflex and breathing
What is the midbrain?
houses the substantia nigra (important in regulating motor activity) and houses relay centres for visual and auditory pathways
What happens when the substantia nigra in the midbrain is not as prominent?
results in parkinson’s disease
What cranial nerves attach to the midbrain?
III and IV
What is the pons?
a ‘bridge’ between the cerebrum and cerebellum
What cranial nerves attach to the pons?
V, VI, VII and VIII
What does the medulla oblongata contain?
vital cardio-respiratory regulatory centres
What cranial nerves attach to the medulla oblongata?
IX, X, XI and XII
What is the spinal cord?
a cylindrical cable of pathways to and from brain and rest of the body
Where does the spinal cord extend from?
the base of the skull (medulla) to L1-L2 vertebrae (ends at coccyx)
What are the enlargements of the spinal cord?
cervical (brachial plexus) and lumbar (lumbosacral plexus)
What covers the spinal cord?
meninges
The brain unlike the spinal cord has (white/grey) matter on the outside and (white/grey) matter on the inside
grey, white
Where are all motor neurons found?
in the spinal cord (sympathetic)
Where all sensory neurons found?
in the ganglia (periphery)
How does a spinal nerve form?
by the dorsal and ventral roots joining up
What is the cerebrum responsible for?
communication between the CNS, PNS and peripheral organ systems
All sensory pathways are_ neural pathways
3
All motor pathways are _ neural pathways
2
What are the 3 major sensory pathways?
dorsal column/ medial lemniscal pathway, spinothalamic (anterolateral) pathway and spinocerebellar pathway
What is the dorsal column/ medial lemniscal pathway responsible for?
joint (limb) position and motion sense (proprioception- conscious understanding of where the muscles are) and light touch
Where does the dorsal column/medial lemniscal pathway go to?
to cortex
What is the spinothalamic pathway responsible for?
pain and temperature
Where does the spinothalamic pathway go to?
cerebrum
What is the spinocerebellar pathway responsible for?
unconscious proprioception (knowing where every single joint/muscle is in space without having to think about it)
Where does spinocerebellar pathway go to?
cerebellum
Where does the dorsal columns synapse for the first time?
when it reaches the medulla
What is the gracile tract in the dorsal column?
sensory axons from lower limb and trunk
What is the cuneate tract in the dorsal column?
sensory axons from upper limb and trunk
What are the steps of the spinothalamic pathway?
1)
1st order neuron from the skin receptors synapses at the dorsal horn
2)
2nd order neuron from dorsal horn then crosses over and ascends on the opposite side of the spinal cord reaching the thalamus
3)
3rd order neuron goes from thalamus to sensory cortex
Which is the pathway without a 3rd-order neuron?
the spinocerebellar pathway
What are the steps of the spinocerebellar pathway?
1)
1st order neuron from receptors in joint capsules, tendons and muscle spindles go to dorsal horn
2)
2nd order neuron from the dorsal horn go to the cerebellum via the dorsal spinocerebellar tracts
What do somatic motor commands effect?
contraction of skeletal muscles
What are the 2 motor neurons that the somatic motor pathways involve?
the UMN (upper motor neuron) and the LMN (lower motor neuron)
What does the upper motor neuron synapse to?
onto the LMN (lower motor neuron)
Where are the cell bodies for the UMN?
in the CNS processing centres
Where are the cell bodies for the LMN found?
in ventral horn of spinal cord or the motor cranial nerve’s nucleus in brainstem
What happens in the destruction of a LMN?
flaccid paralysis of skeletal muscle because none of the muscles can contract (no connection able to pass from LMN to muscle)
What happens in the destruction of an UMN?
spastic paralysis or rigidity because they are firing many action potentials that make all muscles stiff
Where do the LMN in the corticospinal pathway extend axons to?
to regulate muscles of the limbs and trunk
Where do the LMN in the corticonuclear (corticobulbar) pathway extend axons to?
to regulate muscles of the head and neck
What is mental rehearsal?
mentally going through an action, the same neurons will fire as those that fire when you actually do the action
What does the preganglionic fiber travel from?
from the CNS to the autonomic ganglion
Steps of the reflex arc?
1) Arrival of stimulus and activation of receptor e.g. nail poked you
2) Activation of a sensory neuron
3) sensory relayed by the dorsal root to the brain by collateral
4) Information processing in CNS
5) By the ventral root there is the activation of a motor neuron
6) Response by effector e.g. hand lifts away from nail
Can you improve on a reflex? like making it speed up?
No
What are the 6 main nerves in the lumbosacral plexus?
1) Tibial (posterior thigh, toe muscles)
2) Common Peroneal (lateral leg, ‘foot drop’ (dorsiflex)
3) Superior Gluteal
4) Inferior Gluteal
5) Pudendal
6) Posterior Femoral Cutaneous
What are the ventral primary rami of spinal nerves in the lumbosacral plexus?
L4, L5, S1, S2, and S3
What are the 6 main nerves in the lumbar plexus?
Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral Femoral Cutaneous, Femoral, Obturator
What are the ventral primary rami of spinal nerves for the lumbar plexus?
L1, L2, L3, L4
What are the 5 main nerves in the brachial plexus?
1) Axillary (shoulder)
2) Musculocutaneous (biceps)
3) Median (forearm flexors, thenar)
4) Radial (posterior arm and forearm)
5) ulnar (hand muscles)
What are the 5 ventral primary rami of spinal nerves for the brachial plexus?
C5, C6, C7, C8, and T1
What is referred pain?
pain in a visceral (internal) organ that is conveyed onto brain and makes you feel like there is pain on the skin (because brain does not know about viscera)
What is the function of the alveoli?
they are the last tube structures before large clusters of the alveoli
