Exam 4 study Flashcards
What are the parts of a nervous reflex arc?
- Sensory receptor
- Sensory neuron
- Control center
- Effector neuron / motor neuron
- Effector
What are the 3 germinal layers?
ectoderm, mesoderm and endoderm.
Ectoderm gives rise to
sub-specialized to form the (2) neural ectoderm, which gives rise to the neural tube and neural crest, which subsequently give rise to the brain, spinal cord, and peripheral nerves.
What does the mesoderm give rise to?
The mesoderm gives rise to the muscle cells and connective tissue in the body.
What does the endoderm give rise to?
The endoderm gives rise to the gut and many internal organs.
What is CSF?
a clear fluid that surrounds the brain and spinal cord.
What are the functions of CSF?
- Protection (cushion the brain, a shock absorber)
- Chemical stability (circulates nutrients and chemicals filtered from the blood)
- Removes waste
What is interstitial fluid?
The interstitial fluid is the fluid that fills the spaces between cells
Where is CSF produced?
CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles
What is the flow of CSF in the brain?
- Secreted by choroid plexus in lateral ventricle
- Flows through intraventricular foramina to 3rd ventricle
- Choroid plexus in 3rd vent add more CSF
- Flows down cerebral aqueduct to 4th vent
- Choroid plexuses in 4th vent adds more CSF
- CSF flows out 2 lateral apertures and 1 median aperture
- CSF fills subarachnoid space
- at arachnoid villi, CSF is reabsorbed into venous blood of Dural venous sinuses
What are the pyramids?
paired white matter structures of the brainstem’s medulla oblongata
What is the blood brain barrier?
Tight junctions of endothelial cells, make up interior surface of blood vessels
Astrocytes also have feet that extend to the walls of BBB
Circumventricular organs lack BBB bc they require access to blood stream
What are the 2 arteries that blood flows up to the brain?
the carotid arteries and the vertebral arteries
*These arteries supply blood to the front two-thirds of the brain
How does blood flow from the brain?
After emptying into the dural venous sinuses, most cerebral venous blood flows into the internal jugular veins before it is returned to the heart
What cranial nerves control eye muscles?
the abducens, the trochlear, and the oculomotor
What is visceral activity?
The visceral (or autonomic) motor system controls involuntary functions mediated by the activity of smooth muscle fibers, cardiac muscle fibers, and glands
controls smooth muscle, cardiac muscle, and glands
What part of the brain controls our visceral activity?
hypothalamus
What is the worst spinal cord fracture?
C1, C2 - can lead to full paralysis and death
Which vertebrae is most commonly fractured?
Thoracic and lumbar
What is a muscle spindle?
are stretch detectors
What is a muscle spindle receptor?
inform the central nervous system (CNS) about changes in the length of individual muscles and the speed of stretching
What is somatic spinal reflex?
Somatic reflexes involve specialized sensory receptors called proprioceptors that monitor the position of our limbs in space, body movement, and the amount of strain on our musculoskeletal system. … The effectors involved in these reflexes are located within skeletal muscle.
What is the difference between autonomic and somatic reflexes?
Somatic reflexes involve contraction of skeletal muscles. Autonomic reflexes regulate smooth muscle, cardiac muscle, and endocrine glands.
What happens during a stretch reflex?
When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases. This increases alpha motor neuron activity, causing the muscle fibers to contract and thus resist the stretching. A secondary set of neurons also causes the opposing muscle to relax.
Enlargements in spinal cord carry what kind of nerve?
Motor
What is an intersegmental reflex?
A spinal REFLEX arc in which the input (sensory) and output (motor) nerves are connected by tracts running within the spinal cord between different segments of the cord.
What is an intersegmental reflex?
A spinal REFLEX arc in which the input (sensory) and output (motor) nerves are connected by tracts running within the spinal cord between different segments of the cord.
What is a polysnaptic reflex
polysynaptic reflex A reflex action that involves an electrical impulse being transferred from a sensory neuron to a motor neuron via at least one connecting neuron (interneuron) in the spinal cord.
What is an example of a monosynaptic reflex
Knee jerk reflex / stretch reflex
What reflexes are polysnaptic?
Golgi tendon reflex, the withdrawal reflex and the crossed extensor reflex
What is a visceral reflex?
Visceral reflexes involve a glandular or non-skeletal muscular response carried out in internal organ
What reflex is contralteral?
The crossed extensor reflex
What reflex is contralteral?
The crossed extensor reflex
What reflex is ipsilateral?
Golgi tendon
What is an example of a intersegmental reflex arc
Withdrawal reflex
*Polysnaptic
meaning that the outcomes of the reflex get mediated by the stimulation or inhibition of motor neurons from multiple levels of the same spinal cord.
Which of the following is NOT associated with spinal cord?
A. Conduct motor info down the cord
B. Protect neurons in both ascending and descending tracts
C. Conduct sensory info up the brain
D. Coordinate alternating contraction of several muscle groups associated with locomotion
E. Mediate a reflex, such as withdrawal
B - Protect neurons in both the ascending and descending tracts
A nurse pricks your finger to type your blood. You flinch at the pain pulling your hand back. This is called what reflex?
Flexor (withdrawl)
What part of the spinal cord consists entirely of interneuron cell bodies?
Posterior gray horn
A bee sting on the right thigh causes a quick involuntary reaction of the right arm. This is an example of what reflex?
Intersegmental
Interneurons receiving input from sensory neurons are located where?
Dorsal (posterior) horn
Where in the spinal cord is the site of somatic motor neurons?
Anterior gray horn
When the patellar ligament is stretched, it stretches the quadriceps femoris. This reflex will cause the quadriceps femoris to _______ and the hamstrings to _______
Contract, relax
Which branch of spinal nerve has the neurosomas of only SENSORY Neurons?
Posterior dorsal root
Which of the following fractures would be least likely to cause a spinal cord injury?
T12
C2
T5
C6
L4
L4
Where are the autonomic motor neuron cell bodies?
Lateral gray horn
The bundle of nerve roots that occupy the vertebral canal from L2-S5 is called?
Cauda equina
Reflex arcs that only use 2 neurons are called ______refelx arc?
Monosynaptic
Nerves going to the upper limbs to join the spinal cord at the ______ region?
Cervical
A reflex in which the sensory input and motor output are on opposite sides of the spinal cord is called an ____ arc?
Contralateral
Voluntary motor impulses leave the spinal cord via _____ of gray matter
Anterior horn
Where is the site of sensory neuron cell bodies?
Dorsal root gangilon
Which spinal cord tracts carry sensory info?
Ascending
Neurosomas of the anterior root are located in
Gray matter
The anterior rami of the spinal nerves form a nerve plexuses in all regions except ______Region?
Thoracic
What is the structure found between the posterior rootlets and posterior root ganglion?
Posterior root of spinal nerve
Cerebral spinal fluid fills the space between?
Arachnoid mater and pia mater
CSF is formed by______and reabsorbed through arachnoid granulations into_______
Choroid plexuses and dural sinuses
The control of heart rate and blood pressure is based in
Medulla oblongata
What structure is covered by many blood vessels and adheres tightly to the surface of brain?
Pia mater
Damage to the copra quadrigemina would interfere with?
Visual and auditory reflex movements
The dura fold that projects into the longitudinal fissure between cerebral hemispheres is called?
Falx cerebri
If the Pons was damaged what functions would be affected?
Breathing
The brain area that regulates activites that control the state of wakefullness and alertness of the cerebral cortex is?
Reticular formation
Descending fibers from the Pons to the cerebellum pass through what structures of the midbrain?
Cerebral peduncles
Arachnoid granulations are knoblike projections that protrude superiorly through the _____ mater to absorb cerebrospinal fluid into venous blood
Dura
CSF circulates through the …
Subarachnoid space
The folds of the surface of the cerebellum are called
Folia and are less prominent than the cerebral folds
The R & L hemispheres of the cerebrum are connected by
Corpus callosum
What part of the motor pathway inhibits inappropriate movements by initiating and terminating movement properly?
Basal nuclei
What brain structure functions to control the autonomic nervous system and to regulate body temp?
Hypothalamus
The central sulcus separates which lobes?
Frontal from Parietal lobe
What cranial nerve is chiefly responsible for eye movment?
Oculomotor
The anatomy of the cerebrum has which structure?
White matter surrounded by gray matter
All of the following cranial nerves are involved in proprioception except the:
A. Vagus
B. Hypoglossal
C. Accessory
D. Abducens
A. Vagus
Nerves involved in proprioception
Accessory, hypoglassal, abducens,
could be more
Nerve impulses over the ____ nerve cause increased peristalsis and decreased heart rate?
Vagus
What does the Vagus nerve do?
The vagus nerve is 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 does the opic nerve do?
the communication cable between your eyes and your brain.
What does the oculomotor nerve do?
It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid.
What does the trocheler nerve do?
It enables movement in the eye’s superior oblique muscle. This makes it possible to look down. The nerve also enables you to move your eyes toward your nose or away from i
What does the trigeminal nerve do?
for sending pain, touch and temperature sensations from your face to your brain.
What does the abducens nerve do?
It moves the eye outward (abduction) so you can look to the side
What does the vestibulocochler nerve do?
handles balance and equilibrium, while the cochlear nerve is responsible for hearing
What does the hypoglossal nerve do?
enables tongue movement
These muscles help you speak, swallow and move substances around in your mouth.
what does the glossopharyngeal nerve do
Involvement in Taste and Swallowing
what does the accessory nerve do
motor function (movement) to two muscles essential to neck and shoulder movement, the sternocleidomastoid (SCM) and the trapezius, as well as to the larynx (voice box) and other structures in the throat
what does the facial nerve do
carries nerve fibers that control facial movement and expression. The facial nerve also carries nerves that are involved in taste to the anterior 2/3 of the tongue and producing tears (lacrimal gland).
