1 Flashcards
What is the cns ? What does it consist of ?
The central nervous system, brain and spinal cord
What is the pns and what does it consist of ?
The peripheral nervous system, all peripheral nerves and all nervous tissue outside of the cns
What is the somatic division?
It controls skeletal muscle contractions and both voluntary and involuntary reflexes
What is the autonomic division?
It controls subconscious actions, contractions of smooth and cardiac muscles, and glandular secretions
What is the site of intercellular communication in the nervous system?
Synapses
Parasympathetic division has what kind of effect?
Relaxing effect
Sympathetic division has what kind of effect?
Stimulating effect
What is the site of intercellular communication in the nervous system?
Synapses
What is the basic functional unit of the nervous system ?
Neurons
What is the location & function of astrocytes ?
CNS & it regulates blood brain barrier (BBB) & repairs damaged nervous tissue
What is the location and function of ependymal cells?
CBS & forms epithelium that lines central canal of spinal cord and ventricles of the brain
- it produces and monitors CSF
Location and function of oligodendrocytes
CNS & many cooperate to form myelin sheath
- it makes nerves appear white
Location and function of microglia
CNS
- smallest and least numerous neorglia
- clean up cellular debris, wastes, and pathogens
Location and function of satellite cells
PNS & surrounds ganglia (clusters of neuronal cell bodies)
- regulates interstitial fluid around neurons
Location and function of Schwann cells
PNS & forms myelin sheath - a Schwann cell can only sheath one axon - many Schwann cells will sheath an entire axon
What are chemically gated channels?
“Key to open lock”
- chemical must be present to open channel
What is a voltage gated channel?
Will open and close if its within a certain range, action potential open ion channels
What are mechanically gated channels?
Physically pressed on the membrane
Know the step to action potential
& LABEL ON GRAPH
Step 1 - depolarization to threshold, action potential is either trigger or not
Step 2- activation of voltage gated sodium channels
Step 3- inactivation of sodium channels and activation of potassium channels
Step 4 - return to resting membrane potential
What ion triggers ACH release ?
Calcium
What are the steps of chemical synaptic transmission?
- arriving action potential depolarizes axon terminal
- membrane opens voltage-gated calcium ion channels & calcium enters the cytosol of the axon terminal
- ACh diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane. Cation channels open producing graded depolarization due to Na+ inflow
- depolarization ends as ACh is broken into acetate and choline by AChE. Axon terminal reabsorbs chlorine from the synaptic cleft and resynthesizes ACh
What is afferent division ?
Sensory (afferant) carries sensory information
-special sensory receptors : monitor smell, taste, vision, balance and hearing
What is efferent division?
Motor (efferent) : carries motor commands
- from cns to muscles, glands, and adipose tissue (fat)
What composes the posterior root ganglia? What info does it send or receive ?
Axons of sensory neurons & sensory towards brain
What composes the anterior root ganglia ? What infor does it send or receive ?
Axons of motor & involuntary movement to rest if the body
Anatomy of cell body (soma)
-large nucleus and nucleolus
-cytoplasm
-mitochondria
-RER and ribosomes
Anatomy of dendrites
-short highly branches processes extending from cell body (spooky tree)
-receives info from other neurons
-80-90% of neuron surface area
Anatomy of axon
-single long action potential
- axoplasm : cytoplasm of axon
-axolemma : plasma of membrane of axon; covers axoplasm
-initial segment : base of axon
-axon hillock: thick region that attaches initial segment to cell body
- telodendria : fine extensions of distal axon
- axon terminals : tips of telodendria
3 gray horns :
-Posterior horns : somatic and visceral sensory nuclei (incoming info from receptors)
-anterior horns : somatic motor nuclei (outgoing info to effectors)
- lateral horns : thoracic and lumbar segments; visceral motor nuclei
White columns :
-posterior white columns : between posterior median sulcus
-anterior white columns: between anterior horns and anterior median fissure
- lateral white columns : on each side of spinal cord between anterior and posterior columns
What are the three layers of connective tissue around a peripheral nerve ?
- Epineurium : outer most layer (membrane around the nerve), collagen fibers
- Perineurium : middle layer - separates nerve into fascicles (axon bundles)
- Endoneurium : innermost later - surrounds individual axons
What is a plexus?
Interwoven networks of fiber, allows multiples spinal nerves to supply the same structure
Cervical plexus (5)
- Phrenic : controls diaphragm, MOST IMPORTANT
-Lesser occipital nerve : skin on posterior or lateral aspect of head and neck - Great articulate nerve : skin of ear
- Transverse cervical nerve : skin on anterior and lateral aspect of neck
- Supraclavicular : skin of shoulder and clavicle region
Brachial plexus (5)
- Musculocutaneous nerve : muscle and skin nerve. flexed muscles in anterior arm (biceps) skin on anterolateral forearm
- Median nerve : flexor muscles in anterior forearm (wrists) skin on lateral two thirds of hand (thumb index and middle fingers)
- Ulnar nerve : intrinsic muscle of the hand (precise hand movement) skin of medial one third of hand (funny bone)
- Axillary nerve- shoulder muscles (deltoid)
- Radial nerve : posterior muscles of arm and forearm skin posterior side of entire limb (down back of arm) extensor muscles ( triceps)
Lumbar plexus (3)
- Femoral nerve: skin of the anterior and medial thigh, hip, and knee joints. Anterior muscle of thigh (quads)
-Obturator nerve: muscles of medial thigh skin of medial thigh (inside thigh)
-Genitofemoral nerve: skin of external genitalia in both sexes. And cremaster (moves testicles closer or further to the body for temp. Control) muscle in males
Sacral Plexus (3)
- Pudendal nerve: skin of the posterior thigh, gluteal region and popliteal region, pelvic muscles (female muscle keeps all organs inside) (male muscle suspends testes)
- Sciatic nerve: diverges just proximal to the knee.
- Fibular nerve: lateral surface of the leg
- Tibial nerve: calf muscle, skin of the posterior surface of the leg, Posterior leg muscles; big nerves get damages easily
Know the different neuronal circuit patterns
- Divergence: spreads information from one neuron or neuronal pool to many (especially common in sensory pathways )
- Convergence : several neurons synapse on a single neuron
- Serial processing : information moves along a single path, sequentially from one neuron or neuronal pool to the next
- Parallel processing : several neurons/neuronal pools process the same information at the same time
- Reverberation : collateral branches of neurons extend back and continue stimulating presynaptic neurons
What is a spinal tap? Where do they get CSF? What is the function of CSF?
Lumbar puncture or spinal tap withdraws CSF from subarachnoid space, cerebrospinal fluid that carries dissolved gases, nutrients, wastes
What is the differences between ascending tracts and descending tracts?
Ascending tracts - sensory information up toward the brain
Descending tracts - motor commands down to the spinal cord
What are the steps to the reflex arc?
Step 1 - stimulus activates the receptor
Step 2 - activation of a sensory neuron
Step 3 - information processing in the CNS
Step 4 - activation of a motor neuron
Step 5 - response by a peripheral effector (muscle/ gland)
What are the characteristics of polysynaptic reflexes?
- Involve pools of interneurons - may cause excitation or inhibition
- Involve more than one spinal segment - can activate muscles in multiple areas
- Several reflexes may cooperate - to produce a coordinated, controlled response
What are the three meninges layers? What order are they in from deep to superficial?
Dura mater - outermost meningeal layer - makes up tendons
Arachnoid mater - middle meningeal layer
Pia mater - innermost meningeal layer
What are the four regions of the brain?
Cerebrum
Cerebellum
diencephalon
brain stem
What is the cerebral cortex?
It is the surface layer of gray matter
Know the location of the cortexes we covered, what are the cortexes?
- Visual cortex - receives visual information - occipital lobe
*Auditory cortex - receives information about hearing, temporal lobe
*Olfactory cortex - receives information about the smell - temporal lobe
*Gustatory cortex - receives information from taste receptors - insula
*Motor cortex- frontal lobe
*Prefrontal cortex - frontal lobe
*Premarysomatic - periatel
What structures make up the brainstem?
Midbrain - processes sight, sound, and associated reflexes, maintains consciousness
Pons - connects cerebellum to the brainstem
Medulla oblongata - connects the brain to the spinal cord , relays sensory info, regulates autonomic functions ( heart rate, blood pressure, and digestion)
What is the limbic system? What is its function ?
*functional grouping that establishes emotional states
*Links conscious functions of the cerebral cortex with autonomic functions (why depression and PTSD alter physiological responses like heartbeat)
*Facilitates memory storage and retrieval
In the hypothalamus, what is the function of the three centers present there?
*mammillary bodies: control reflex eating movements
*Infundibulum: connects the hypothalamus to the pituitary gland
*emotions
*Automotive function: subcontinent control
*Hormone production: Oxytocin is made in the hypothalamus as well as other hormones
*allows you to hold your breath. But it eventually tells you to breathe. (Controls autonomic function as well as voluntary)
*Behavioral drives regulated by the hypothalamus:
Feeding center
Thirst center
Satiety center (regulates food intake)
Cerebrum
largest part of adult brain, controls higher mental functions such as conscious thoughts, intellect, memory, etc.
Visual cortex
receives visual information, in the occipital lobe
Auditory cortex
receives information about hearing, in temporal lobe
Olfactory cortex-
receives information about smell, in the temporal lobe
Gustatory cortex
receives information from taste receptor, in the insula
Prefrontal cortex
performs abstract intellectual functions (predicting consequences of actions)
Cerebellum-
coordinates repetitive body movements
Arbor vitae
tree of life”, highly branched, internal white matter of the cerebellum
Thalamus
relays and processes sensory information
Pineal gland-
secretes melatonin
Pituitary gland
major endocrine gland, integrates nervous and endocrine system
Hypothalamus
emotions, autonomic function, hormone production
mammillary bodies
control reflex eating movements
Infundibulum
narrow stalk, connects hypothalamus to pituitary gland
Hippocampus
establishes emotional state, memory storage
Fornix
tracts of white matter, connects the hippocampus to hypothalamus
Reticular Formation
grey and white matter with embedded nuclei
