Exam 4 study Flashcards
(87 cards)
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.
