W5: NeuroPsych Flashcards
Nervous system overview
Central: Brain and spinal cord
Periph: cranial nerves, spinal nerves and pathways (neurons/NT)
The _____ is an integrated circuit composed of millions of neurons and receives 15-20% of cardiac output. This organ allows people to reason, function intellectually and express themselves.
Brain
Nerve injury- 2 pathways (lecture-more)
- Axonal
- Demylinization
Perpih Nervous System:
Somatic: motor/sensory, regulating motor control of skeletal muscle
Autonomic: motor/sensory regulating body’s internal environ. through involuntary control of organs
Sympathetic
Parasympathetic
Neurons what do they do and the 3 components function
Neuron: primary info/comms. cell; vary in size/structure
Cellular:
microtubules (transport)
Neurofibrils (structure sup)
Nissl Substances (protein synth)
-Some neurons-olfactory continue to divide, others die if not needed
- Cell body (soma) located in CNS; nuclei-desnsely packed
ex: ganglia and plexuses-groups in the PNS - Dendrites (receptive portion)
-sends signals to the cell body
-Dendritic Zone: receptive portion of neuron rec’ing signals and cont. conduction - Axons: (carry away from cell)
Axon hilcock: cone-shaped, organelle-free, area where axon leaves the cell body-closest portion has lowest threshold for stim.
Axons: what happens if injured
Myelin: segmented layer of lipids; insulating,
myelin sheath: Entire membrane; formed and maintained by SCHWANN cells
endoneurium: delicate layer of connective tissue around each axon
Neurilemma (Schwann sheath) thin membrane b/w myelin sheath and endoneurium
Neuroglia=”nerve glue”
5-10x > than neurons
astrocytes: fill space b/w neuron & surrounding Blvessels
Oligodendroglia: deposit myelin within CNS
Microglia: remove debris
Ependymal: line CSF cavities
Schwann Cells: aka neurolemmocytes
glial cells, wrapping around/covering axons in the PNS
Form/maintain myelin sheath
myelinated: wrapped tightly, many times around axons, creating-NODES of RANVIER
increasing velcocity of signal
Neurotransmitters-common types & effects postsynaptically
Types:
norepinephrine
acetylcholine
dopamine
histamine
serotonin
post-synapse:
excited-depolarized
inhibited: hyper polarized
Neurotransmitters & receptors
When neurotransmitters release their contents into the ______ ____, they diffuse across and bind to receptors on the ____ synaptic neurons and trigger an ____ ______
1 synaptic cleft, 2. post, 3. action potential
The parasympathetic system is also known as the ______ system due to it’s affinity for _______ which binds to ______ receptors
cholinergic, 2. acetylcholine, 3. muscarinic
Discuss Action Potential- all or none phenomenon
An action potential is a brief reversal of the electrical potential across the membrane of excitable cells like neurons and muscle cells. It is the fundamental mechanism by which information is transmitted along these cells.
threshold potential -55mV, voltage gated NA channels open allowing influx of + sodium—rapid depolarization to +30mV
Propogation of AP:
The depolarization zone propagates away from the initial site, causing adjacent regions to also depolarize in a wave-like manner by opening voltage-gated Na+ channels. This allows the action potential to travel rapidly along the axon toward the axon terminals
In myelinated cells, the AP jumps from node of Ranvier to Node, increasing in velocity
Repolarization and refractory
after peak, NA channels deactivate allowing in K+, therefore repolarinzing membrane back to resting potential.
During absolute refractory: right after peak, the neuron CANNOT generate another charge
Anatomy of the brain-3 major divisions
- Forebrain: two cerebral hemispheres
- Midbrain: corpora quadrigemina, tegmentum, and crebral peduncles
- Hindbrain: cerebellum, pons, and medulla
Forebrain: telencephalon
Cerebrum
-cerebral cortex
-basal ganglia
-Gyri, sulk, and fissures
-gray matter (nuclei) and white matter (numberous tracts)
Brainstem: reticular formation
Midbrain, medulla, and pons
Retic: network of connected nuclei that reg. vital reflexes (cardio/resp)
maintains wakefulness
w/ cerebral cortex is refered to as reticular-activating system
Frontal Lobe: (know functions for stroke purposes)
Prefrontal: goal-oriented behavior; short-term mem/recall
premotor: programs motor movement; in the basal ganglia or extrapyramdial sys
efferent pathway outside of medulla pyramids.
primary motor area: homunculus (little man)
corticospinal tracts (pyramidal system) DESCEND the spinal cord. Contralateral control
Broca speech area:
Motor aspect of speech
Parietal, occipital & temporal lobes
parietal: somatic sensory input
occipital: visual cortex
temporal: auditory cortex
wernicke area (rec/interpr speech)
long-term memory
Corpus callous, limbic system, and Diencephalon
Corpus callous: aka transverse commissural fibers; connects the two hemispheres
Limbic: primitive behaviors/responses, visceral reactions to emotion/motivation, mood, feeding, biorhythms, and sense of smell;
Consolidation of memory
Diencephalon-
-epithalamus
-thalimus
-hypothalamus
-subthalamus
The _______ is composed of four areas: the ____ which forms the roof of the third ventricle and superior area, the ______ manages afferent (sensory) impulses to the cerebral cortex, the ______ maintains a constant internal environment by controlling the ______ nervous system via body temperature and endocrine function and finally the ______ serves as a center for motor activities.
Diencephalon, 2. epithalamus, 3. Thalamus, 4. hypothalamus, 5. autonomic, 6. subthalamus
Midbrain (mesencephalon)
Corpora quadrigemina (tectum): superior vision/inferior auditory
Tegmentum: red nuclei (motor output) and substantia nigra (synth dopamine)
Cerebral peduncles
Cerebral Aquaduct (Silvius) carrie CSF
HindBrain: (metencephalon)
Cerebellum-conscious & union. muscle synergy; maintains balance/posture
Damage- ipsilateral (same side) loss of equillibrium, bal, and motor coordination
Pons: helps control respiration
Medulla oblongata (myelencephalon) controls:
HR, RR, BP, cough, sneeze, swallow, & vomitting
Spinal cord: reflex arc
-receptor
both afferent & efferent neurons
Motor effectrs from the reflex arcs generally occur before the perception of the event in the higher centers of the brain
upper and lower neurons