Dendrites of postsynaptic neuron contain binding sites for neurotransmitters
1. Impulse travels down axon to synaptic bulb (neurotransmitters are released) 2. Neurotransmitters cross synaptic cleft 3. Neurotransmitters bind to receptors on plasma membrane of postsynaptic neuron *Neurotransmitter action does not last long continuously removed from synaptic cleft by enzymes or reuptake.
Chemical messengers involved in nerve transmission are stored in vesicles and can be either excitatory or inhibitory
Contains: auditory & olfactory areas Wernicke area - Language comprehension
degree of mental alertness and responsiveness
The 4 levels of consciousness recorded as brain wave patterns are?
Beta, Alpha, Theta, Delta
Wakeful consciousness & mental activity REM sleep appears as beta waves
Awake & relaxed
Drowsiness & dreamlike awareness used in hypnosis to access deep-rooted memories
deep sleep from which the subject is not easily aroused
Diencepholon is located in
the center of the brain
nearly 80% of diencephalon Relays sensory information to appropriate part of cerebrum
Regulates ANS and endocrine system Controls hunger and thirst, anger and aggression, hormones, sexual behavior and sleep patterns
Sits in sella turcica of sphenoid bone
Located below corpus callosum
Cerebellum is located?
posterior and inferior to cerebrum
muscle tone, posture, balance
Brainstem is continuous with
There are 3 main divisions of the Brainstem
Mid-brain Pons Medulla oblongata
conducts impulses from cerebrum to pons conducts impulses from spinal cord to thalamus
bridges cerebellum and cerebrum with spinal cord
Medulla oblongata is located?
inferior portion of brainstem
conducts sensory & motor impulses between brain & spinal cord
Medulla oblongata contains?
Respiratory center Cardiovascular center Vasomotor center
This contains may crossing over fibers called Decussation
Semipermeable wall of blood capillaries. Prevents or slows passage of some chemicals and pathogens from blood into CNS
This has thick basement membrane and glial cells
Exits skull via foramen magnum and is known as the information highway and a integrating center.
lower portion of cord shaped like a horse tail
Fibrous extension of cauda equina
A cross section of the spinal cord reveals this?
White matter located on periphery and Gray matter located in center(H-shaped)
Gray matter in H contains 3 regions called horns?
Anterior horn Lateral horn Posterior horn
White matter found in the spinal cord is called
There are 3 columns in the spinal cord column?
Anterior column Lateral column Posterior Column
Collection of nerves running up and down spine
There are types of tracts
Ascending - Sensory (afferent) impulses travel up cord Descending - Motor (efferent) impulses travel down cord
connective tissue coverings surrounding brain and spinal cord. It has 3 layers
Meningeal layers are?
Pia Mater, Arachnoid, Dura mater
Innermost delicate layer attaches to brain and spinal cord
Middle later resembling a spider's web
Outermost dense layer lies against skull and spinal column
Subarachnoid, Subdural, Epidural
Fluid circulating around brain and spinal cord
Functions of the Cerebrospinal Fluid
Supplies O2 and nutrients, Carries away wastes, Acts as a shock absorber
Arise from brain 12 pairs
arise from spinal cord 31 pairs
CN V(5) Trigeminal
contains 3 branches; pain, temperature and motor innervation for muscles of mastication.
CN VII(7) Facial
Facial expression and produces both saliva and tears.
CN X(10) Vagus
Receives sensations from external ear and external auditory canal and thoracic and abdominal organs. Aids digestion. Regulates heart activity
part of spinal nerve that connects to spinal cord.
2 types of nerve roots
Ventral (anterior) Dorsal (posterior)
Cluster of nerve cell bodies in PNS
Network of intersecting nerves in PNS
There are 3 major plexuses?
Cervical, Brachial, Lumbosacral
Area of skin supplied by specific sensory nerve root
Involuntary, predictable response to a stimulus
carries stimulus to spinal cord connects motor neuron to appropriate muscle or gland
Autonomic Nervous System has 2 divisions?
Sympathetic & Parasympathetic
Parasympathetic Nervous System
Supports functions that conserve & restore energy - (Maintains homeostasis and regulates urinary & digestive processes, pooping and storing nutrients)
Most active under calm conditions
Referred to as craniosacral outflow
Sympathetic Nervous System
Uses body energy for periods of physical exertion or emotional stress
Adrenals secrete ephinephrine
Referred to as thoracolumbar outflow
Sympathetic Nervous System
Law of Facilitation
When an impulse has passed once through a certain set of neurons to the exclusion of others, it tends to take the same course of future occasions and each time it traverses this path the resistance is less.