Nervous System Flashcards
What wraps the external neurilemma (nerve fibers)?
Endoneurirm which is loose CT
What is a fascicle?
Bundle of nerve fibers
True or false -
Perineurium is what wraps the fascicle.
True
What is made of dense irregular CT and wraps the entire nerve?
Epineurium
What penetrate the CT covering on the nerves?
Blood vessels
How many pairs of spinal nerves are there?
31 pairs (mixed nerves)
What are spinal cords formed of?
Two roots - posterior root for sensory input to the spinal cord
Anterior root motor output out of the spinal cord
When the roots unite within the vertebral column it forms ________
Spinal nerve
Where do the spinal nerves exit?
Intervertebral foramen
What are the three branches of nerves that come from the vertebra?
Posterior ramus
Anterior ramus
Maningral branch
True or false -
The anterior ramus supplies the muscles, skin, and joints in the spine or back
False -
The posterior ramus supplies the muscles, skin, and joints in the spine or back
What does the anterior ramus do?
Supplies anterior and lateral skin, muscle, and limbs
What does the maningeal branch do?
It reenters the vertebral canal and supplies nerves to meninges, vertebra, and spinal ligaments
What is a plexuses (web)?
When anterior ramus branch and re-connect repeatedly.
What does the cervical plexus in the neck supply? (C1-C5)
Supplies neck and phrenic nerve to the diaphragm
What does the Brachial plexus near the shoulder supply? (C5-T1)
Supplies the upper limbs and some of the shoulder and neck
True or false -
The Lumbar plexus supplies the entirety of the lower limbs
False -
The lumbar plexus supplies the abdominal walls, anterior thigh, and genitalia
What does the sacral plexus supply to? (L4, L5, and S1 to S4)
Supplies the other parts of the lower limbs and trunk that the lumbar plexus does not.
What does the coccgeal plexus supply? (S4, S5, Co1)
Supplies the skin adjacent to the sacrotuberous ligament
What is the somatosensory function of spinal nerves?
To carry sensory signals from bones, joints, muscles, and skin
What is the motor function of the spinal nerves?
To stimulate muscle contractions , along with autonomic fibers to blood vessels, muscles, and other organs
What are four things that happen during reflexes?
Quick - simple neural pathways
Involuntary - without control
Stereotyped - same every time
Stimulation - needed to produce reaction
What are the somatic reflex arc steps?
Receptor - Sensory nerve ending or simple sense organ in the skin, muscle or tendon (simple-> heat, pain)
Afferent (sensory) nerve fibers - Axon carries signals –> (posterior horn) spinal cord/ brainstorm
Integrating center - Contact between neurons and gray matter
Efferent (motor) nerve fibers - (anterior horn) signal to skeletal muscle
Effector - Carries out response
What makes up the grey matter in the brain?
House the motor neurons and interneuron cell bodies, dendrites, and unmyelinated axons.
What parts of the brain is made up of grey matter?
Cerebral cortex (surface of adult brain), Cerebral nuclei within the white matter
What is white matter made of?
Bundles of axons
Where is white matter found in the brain?
Deep in the grey matter.
What is the function of white matter?
Connect one part of the brain with another using tracts
________ is the connective tissue that surrounds the brain.
Meninges
What are the three functions of the meninges?
Separate the brain from the bone
Protect blood vessels (some drain the blood from the brain)
Contain and circulate cerebrospinal fluid
What are the three layers of the meninges?
Pia mater: thin, innermost layer attached to the brain
Arachnoid mater: web of fibers, middle layer
Dura mater: tough outer layer with two sublayers
What are the two layers in the Dura mater?
Superficial periosteal layer: layers are fused where they separate from the dural sinus
Deep meningeal layer: Extends into the spinal cord to form dural sheath
What is the cranial dural septa?
Menigeal layer that extends into the brain to form double-layered dura
_______ projects into the longitudinal fissure and separates the left and right cerebral hemisphere
Falx cerebri
________ is the horizontal fold that separates the cerebrum from the cerebellum
Tentorium cerebelli
______ separates the left and right cerebellar hemispheres
Falx cerebelli
What is the purpose of the cranial dural septa and what does it attach to?
Partition and support to the brain and attaches to the cranial bones at the foremen magnum, sella turcica, critsal galli
What is a dural venous sinus?
A sinus in the brain that is filled with blood, they are filled by veins that drain and into the internal jugular veins
What are ventricles?
Internal chambers within the brain
What is cerbrospinal fluid?
Clear, colorless liquid that fills the ventricles, canals, and covers external surface of the CNS
True or false -
The choroid plexus is a spongy mass of blood capillaries on the floor/wall of each ventricle.
True
What are the functions of the CSF?
Buoyancy - suspended in place by fibroblasts in arachnoid mater, allows brain to attain considerable size without being impaired by its own weight, without out the CSF the pressure would kill the nervous tissue
Protection - From striking cranium with head it jolted
Chemical Stability - CSF flow removes metabolic waste from nervous tissue and regulates the chemical environment
What is the flow of the cerebrospinal fluid? (8 steps)
- CSF is secreated by choroid plexus in each lateral ventricle
- CSF flows through interventricular foramina into the third ventricle
- Choroid plexus in third ventricle 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 medium aperture
- CSF fills subarachnoid space and bathes external surfaces of the brain and spinal cord
- At archnoid granulations, CSF is reabsorbed into venous blood of dural venous sinous
What is the function of the blood brain barrier?
Regulates what substances enter the brain.
What is the blood brain barrier made of, how is it made and what is the significance of this?
Made of astrocytes that cover capillaries with perivascular feet, which causes endothelial cells to form a tight junction. This tight junction makes substances pass though the cells rather then around them
What things can go through the blood brain barrier and what things cannot?
Permeable: water, glucose, Co2, alcohol, caffeine
Non permeable: antibiotics and cancer drugs
True or false -
The brain stem is apart of the spinal cord
False - it is between the cerebrum and lower body that functions as a passageway for tracts
What are the three regions of the brain stem?
Medulla oblongata
Pons
Midbrain
What is the reticular formation and what are the functions?
It is a web of grey matter that lacks boundaries and is in all levels of the brain stem.
Helps with somatic motor control - muscle tone, balance and posture.
Central pattern generators
Gaze centers - track and fixate on objects
Pain modulation
Sleep and consciousness
Habitiuation - ignores repetitive stimui
What part of the brain do all ascending and descending fibers pass through?
Medulla oblongata
What three sutonomic nuclei does the medulla contain? What do they do?
Cardiac center - regulates heart rate and its strength of contraction
Vasomotor center - control blood pressure be regulating contractions and relaxation of smooth muscle in walls of arterioles
Medullary respiratory center - regulates respiratory rate
What are the parts of the posterior medulla and what are the functions?
Nucleus cuneatus (upper limbs) and nucleus gracilis (lower limbs) - relay somatic sensory info to thalamus
What are the parts of the anterior medulla and what are the functions?
Pyramids - descending fibers, motor signals to skeletal muscles
Olives - relay center for signals to cerebellum, used for balance and coordination
What centers are found in the pons?
Sleep and respiratory centers
Pontine respiratory centers - regulate breathing (skeletal muscle)
Superior olivary complex- Nuclei receive auditory input and locate sound source
What are the main sections of the midbrain and what are there functions?
Tegmentum - Regulation and coordination of fine motor activities
Substantia nigia - produce dopamine tat prevent unwanted body movements
Tectum – Reflexes for blinking, focusing, pupillary dilation and constrictions. Tracking movements with eyes. Auditory reflex
What is the second largest part of the brain?
Cerebellum
True or false -
The cerebellum has more then half the brains neurons
True
What is the function of the cerebrallar peduncles?
Connect the brainstem and the cerebellum. They are fibers that carry signals toward and away
What are the major functions of the cerebellum?
Coordination of fine-tune skeletal movement
Stores memories of previously learned movement patterns
Adjust muscle actives to maintain equilibrium and posture
What are the three parts to the diencephalon?
Thalamus, hypothalamus and epithalamus
What surrounds the third ventricle?
Diencephalon
What is the relay center for all conscious sensory impulses?
Thalamus
What part of the brain is responsible for olfactory reflexes and emotional responses
Hypothalamus
What are the functions of the hypothalmic nuclei?
Hormone secretion Autonomic effects - influences heart rate, blood pressure, gastrointestinal secretion, motility Thermoregulation - Shivering, sweating Food or water intake Sleep and circadian rhythms Memory Emotional behavior and sexual response
What part of the brain houses the pineal gland?
Epithalamus - It secretes melatonin
What is the largest part of the brain?
Cerebrum
What are the lobes of the cerebrum?
Frontal, Parietal, Occipital, Temporal, and insula
What is the cerebral cortex?
The outer portion of the cerebrum
What are the functions of the cerebral cortex?
Higher brain functions Interpret sensory impulses Stores and recall memory Control thought, intelligence, and personality Voluntary movement Consciousness
What separates the two hemispheres of the cerebrum?
Corpus Callosum
True or False -
The frontal lobe is responsible for voluntary motor function, motivation, aggression, sense of smell, mood, personality, and decision making
True
True or False -
The parietal lobe is responsible for reception and integration of visual input
False - the occipital lobe is responsible for reception and integration of visual input
True or false -
The temporal lobe is responsible for reception and evaluation for smell and hearing
True
True or false -
The parietal lobe if responsible for reception and evaluation of sensory info
True
What is the function of the insula?
Helps in understanding spoken language, taste, and integrates information from visceral receptors
True or false -
Central white matter can process information
False -
Central white matter can not process information
What is the central white matter made up of?
Myelinated nerve fibers (axons)
What is the purpose of the central white matter?
Full of tracks that are used to communicate between different areas, info between sensory association and motor areas, and connects the two hemispheres
What are the three types of tracts and the function?
Association tract - connects areas within on hemisphere
Commissural tracts - connects two hemispheres, corpus collosum
Projection tracts - connects cerebrum to lower areas like the spinal cord
What are the two types of association tracts?
Arcuate - fibers within a lobes
Longitudinal fascouli - connect different lobes of same hemisphere
What three large sections of the brain are found in the cerebrum?
Cerebral cortex
Basal nuclei
Limbic system
What are the functions of the lymbic system?
Processes and experiences emotions Memory formation (learning)
What are the three big parts of the lymbic system?
Cingulate gyrus - arches over corpus callosum in frontal and parietal lobes
Hippocampus - in medial temporal lobe
Amygdala - immediately rostral to hippocampus
What is the emotional center in the lymbic system?
Amygdala stores and codes memories based on emotions, this can be from pain, pleasure, sorrow
What part of the lymbic system is responsible for learning and memory?
Hippocampus - makes short term memory into long term memory. Emotionally charged events
What are the Basal (cerebral) nuclei made of?
Grey matter that are deep in the brain, lateral to the thalamus
What is the function of basal nuclei?
Integrate motor commands, correct muscle groups activated
What are the parts of the Corpus stratum and what are the functions?
Caudate nuclei - helps coordinate walking (arm and leg movement)
Lentiform nucleus - involved in movement and muscle tone
What is the function of primary cortices?
Receive input from sense organs/brain stem
Issue motor nerve fibers to brain stem
What is the function of association cortices?
Interpretation of sensory input
Planning of motor output
Thought processing
Storage/ retrieval of memories
What are the special senses and what part of the brain is responsible for them?
Vision - primary visual cortex, occipital lobe. Visual association area, posterior parietal/inferior temporal lobe
Hearing - Primary auditory cortex, temporal lobe. Auditory association area, temporal lobe
Equilibrium - Primary, cerebellum and brain stem nuclei. Association area, Thalamus
Taste - primary gustatory cortex, inferior end of post central gyrus
Smell- Primary olfactory cortex, medial surface of temporal lobe
Orbitofrontal cortex - gustatory and olfactory (and visual) association
What provides awareness of stimulus?
Primary somatosensory cortex
Sensory regions are connected to _____ areas via _______ areas.
Sensory regions are connect to motor areas via association areas
What makes cognitive sense of stimui and passes information to the other parts of the brain (emotion, memories)?
Somatosensory association area
What part of the frontal lobe has the intention to contract skeletal muscle? What are its other functions?
Motor association - plan behavior, sequence muscle contractions
What are the functions of the prefrontal cortex?
Motivation, foresight to plan and initiate movements, emotional behavior, mood
What is the purpose of the frontal eye field?
To control and regulate eye movements
What cortex is responsible for voluntary skeletal muscle activity?
Primary motor cortex
What are the functions of the basal nuclei?
Filters signals from cerebral cortex
Planning and execution
Practiced behaviors - writing, typing, driving
Walking and tying shoes
What are the functions of the cerebellum?
Coordination
Learning motor skills, maintain muscle tone and posture, coordinates eye and body movements
Monitors body position
What part of the brain recognizes and comprehends spoken and written language?
Wiernicki area
Formulated plan to speak based of memories and how language works
What part of the brain is responsible for the muscular movement involved in speech?
Motor speech area
Generated motor progra for muscles, cheeks, and tongue to produce language
Program sent to primary motor cortex
Explain motor nerve tract pathways
Direct pathways - maintenance of muscle tone, control and speed of fine motor skills
Indirect pathways- less precise movements, body coordination/posture, can aid direct pathways
