UNIT 10- NERVOUS SYSTEM Flashcards
What happens on day 14 after conception?
Embryo split into 3 germ layers- ectoderm, mesoderm and endoderm
What happens on day 20 after conception?
formation of neural tube- develops into brain and spinal cord
What happens on week 4 after conception?
organizes in 3 bulges: prosencephalon, rhombencephalon and mesencephalon
What happens on week 5 after conception?
bulges organized into 5 regions: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
What produces CSF?
Choroid plexus
Central sulcus divides ________ and _________ lobes, whereas lateral sulcus divides __________ from ____________
Central sulcus divides parietal and frontal lobes, whereas lateral sulcus divides temporal lobe from parental and frontal lobes
Precentral vs postcentral gyri
Precentral gyrus- voluntary muscle movement (part of frontal lobe)
Postcentral gyrus- somatosensory info from body (part of parietal lobe)
Functions of the 5 cerebral lobes
- Frontal- voluntary motor control
- Parietal- somatosensory
- Occipital- vision
- Temporal- auditory
- Insula- memory and pain
UMNs of precentral gyrus synapse on ________ which is relayed to _________ and __________ which form the ______________
UMNs of precentral gyrus synapse on basal nuclei which is relayed to thalamus and cerebellum which form the accessory motor system (how rapid a movement will occur and how large the movement will be)
What is the function of the limbic system and how does the fact that there are no connections between limbic and cerebral cortex affect the function?
The limbic system is responsible or emotion, motivation, LTM and smell
The fact that there are no connections between limbic and cerebral cortex demonstrates why humans do not have conscious control over emotions
Mesencephalon is made up of…(4)
- Corpora quadrigemina- visual auditory reflexes
- Cerebral peduncles- ascending and descending tracts
- Red nucleus- connect cerebrum to cerebellum, motor coordination
- Substantia nigra- dopaminergic nigrostriatal system
Ascending afferent nerves are involved in _______ processes and innervate the ________ root, whereas descending efferent nerves are involved in ________ processes and innervate the _______ root. These combine to form ____________ nerve
Afferent nerves are involved in sensory processes and innervate the dorsal root, whereas efferent nerves are involved in motor processes and innervate the ventral root. These combine to form peripheral spinal nerve
What are the 2 major ascending tracts? What are the 2 major descending tracts?
Ascending (sensory) tracts:
1. Spinothalamic- pain, temp
2. Spinocerebellar- sensory, proprioceptive info
Descending (motor) tracts:
1. Pyramidal- voluntary motor control
2. Extrapyramidal- involuntary motor control
What are the 3 requirements of a reflex arc?
- sensory receptor to detect stimulus and sensory neuron to transmit signal to spinal cord
- motor neuron to transmit involuntary response to effect/target
- an effector organ for response
What is the flexor reflex?
reflex in response to painful stimuli
Nerves that innervate skeletal muscle are _______ and ________, whereas nerves that innervate smooth muscle, cardiac muscle and glands are _________ and ___________
Nerves that innervate skeletal muscle are somatic and voluntary, whereas nerves that innervate smooth muscle, cardiac muscle and glands are autonomic and involuntary
There are ___ cranial nerves and ___ spinal nerves
12 cranial, 31 spinal
What is the structure of somatic motor neurons? What is the structure of autonomic motor neurons?
Somatic motor neurons- cell body is located in the CNS, axon innovates skeletal muscle (voluntary)
Autonomic motor neurons- involves 2 neurons. First neutron (preganglionic) has cell body in the grey matter of spinal cord axon synapses with second neuron (postganglionic) whose axon innervates the effector/target organ (involuntary)
In the sympathetic division myelinated preganglionic axons exit the _________ in______ of spinal nerve. Unmyelinated postganglionic axons travel to __________ as part of the spinal nerve.
In the sympathetic division myelinated preganglionic axons exit the spinal cord in ventral roots of spinal nerve. Unmyelinated postganglionic axons travel to effector/target organs as part of the spinal nerve.
What system stimulates the adrenal medulla to secrete epinephrine and norepinephrine?
Sympathetic NS stimulates the adrenal medulla to secrete NE and epinephrine
Parasympathetic preganglionic fibers originate in ________ and synapse in ganglia located ____________ or _______ innervated organs which supply postganglionic fibers that synapse with __________
Parasympathetic preganglionic fibers originate in BRAIN and synapse in ganglia located NEXT TO or IN innervated organs which supply postganglionic fibers that synapse with EFFECTOR CELLS
What is the major structural difference between sympathetic and parasympathetic innervation of target areas?
In the sympathetic division, the ganglion cells are typically outside the target organ in parasympathetic the ganglion cells are inside or next to the target organ
What is the MAIN difference between the somatic and autonomic divisions of the motor PNS division?
ANS neurons do NOT directly innervate their target area, they require a two neuron circuit for the motor response (and autonomic ganglia as a relay station)
Sympathetic cells make…
Parasympathetic cells make…
Sympathetic cells make norepinephrine
Parasympathetic cells make acetylcholine
