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Flashcards in CNS, ANS, CN Deck (55):

what does the human brain consist of

cerebrum (cerebral cortex)
diencephalon (thalamus, hypothalamus, pineal gland)
midbrain (also called the mesencephalon, a part of the brainstem)
pons (connects to the cerebellum and medulla and is part of the brainstem)
medulla oblongata (connects to the spinal cord and is part of the brainstem)


what are the lobes of the cerebral cortex

frontal lobe
parietal lobe
occipital lobe
temporal lobe


what is the major fiber pathway that interconnects the two hemispheres

corpus callosum


where is the gray and white matter in the brain

the convulated surface of the cerebral hemispheres containing the cortical neurons comprises the gray matter and lies above the deeper situated white matter, which comprises the fiber connections that course from deeper brain regions or the interconnections that permit communication between the two hemispheres


what is the thalamus

the "Executive secretary" of the cortex, because it is reciprocally connected to the cortex and conveys motor, sensory, and autonomic information from the brainstem and spinal cord.


what is the hypothalamus

it lies beneath the thalamus, and its connections with the pituitary gland reflect its important role in neuroendocrine function


what is the pineal gland

an endocrine organ that secretes melatonin and is important in regulation circadian rhythms


what are the colliculi

superior and inferior culliculi are sensory nuclei associated with visual reflexes and auditory reflexes, respectively. Are also part of the midbrain


what is the function of the basal ganglia and what does it include

provide subconscious control of skeletal muscle tone and coordination of learned movements. Once a voluntary movement is initiated cortically, the natural rhythm and patterns that we take for granted in walking or reaching for objects are controlled subconsciously by the basal ganglia.

it includes:
- caudate nucleus
- putamen
- globus pallidus


what are some disorders affecting the basal ganglia

Huntington's disease: results in a hereditary loss of basal ganglia and cortical neurons that leads to a hyperactive state of involuntary movements. The jerky movements of this disease almost resemble a dancer out of control, and the term chorea ("dance") aptly characterizes this fatal condition. In its late states, mental disorientation is common.

Parkinson's disease: resulting from the degeneration of the dopamine-secreting neurons of the substantia nigra, this progressive disease results in bradykinesia (slow movements), resting rhythmic muscular tremor, muscular rigidity, stooped posture, a masked or expressionless face, and a shuffling gait.


what is the limbic system

it is a functional group of structures that form a ring ("limbus") around the diencephalon. The limbic system participates in emotional behaviors (fear, rage, pleasure, and sexual arousal) and in the interpretation of internal and external stimuli (linking conscious functions with autonomic functions, and aspects of memory and retrieval)


functions of the hippocampus and amygdala

functionally, the hippocampus and amygdala are important in memory consolidation and access. Moreover, the hippocampus plays a role in spatial relationships, whereas the amygdala associates a variety of sensory memories and links them to our emotional responses, especially fear and aversion.


Name some characteristics of the thalamus

The right and left thalamus are seperated by the 3rd ventricle and form the major portion of the diencephalon (about 80%)

The central location of the thalamus is representative of its importance; essentially, no sensory information, except olfactory information, passes to the higher cortical regions without synapsing in the thalamus. Thus the thalamus has been characterized as the "executive secretary" of the brain because it sorts and edits information.

Sensory, motor, and autonomic information from the spinal cord and brainstem is conveyed to the cortex via the thalamus. Likewise, the thalamic nuclei are reciprocally interconnected with the cortex. A white matter tract, the medullary laminae, runs through the thalamus and relays information to the cortex.


Characteristics and function of the hypothalamus

the hypothalamus lies below the thalamus and the 3rd ventricle, it is part of the diencephalon.

Functionally, the hypothalamus is very important in visceral control and homeostasis and possesses extensive connections with other brain regions.

Its main functions include:
- regulation of the autonomic nervous system (hear rate, blood pressure, respiration, and digestion)
- expression and regulation of emotional responses
- water balance and thirst
- sleep and wakefulness related to our daily biological cycles
- temperature regulation
- food intake and apetite regulation
- reproductive and sexual behaviors
- endocrine control


major functions of the preoptic and anterior hypothalamic area

heat loss center: cutaneous vasodilation and sweating


major functions of the posterior hypothalamic area

heat conservation center: cutaneous vasoconsctriction and shivering


major functions of the lateral hypothalamic area

feeding center: eating behavior


major functions of the ventromedial hypothalamic area

satiety center: inhibits eating behavior


major functions of the supraoptic (subfornical organ and organum vasculosum) hypothalamic area

ADH and oxytocin secretion


major functions of the paraventricular hypothalamic area

ADH and oxytocin secretion


major functions of the periventricular hypothalamic area

secretion or releasing hormones for the anterior pituitary


General functions of the cerebellum

- Regulate the postural muscles of the body to maintain balance and stereotyped movements associated with walking
- Adjust limb movements initiated by the cerebral mortor cortex
- paticipate in the planning and programming of voluntary, learned, skilled movements
- play a role in the eye movement
- play a role in cognition


name the anatomical lobes and the functional zoned of the cerebellum

anatomical: anterior, posterior, and flocculonodular lobes

functional zones:
- lateral hemisphere: planning movements
- paravermis (intermediate) zone: adjust limb movemebts
- vermis (in the midline): postural adjustments and eye movements


name the cerebellar peduncles and what they connect to

superior: connects the cerebellum to the diencephalon
middle: connects the cerebellum to the pons
inferior: connects the cerebellum to the medulla


where is CSF produced

it is produced by the choroid plexus, which is found in the floor of each lateral ventricle


how much CSF is produced in a 24 hr period and what is the function of CSF

about 500 mL of CSF is produced in a 24 hr period and it functions to:
- support and cushion the brain and spinal cord
- fulfill some of the functions normally provided by the lymphatic system
- fill the 150 mL volume of the subarachnoid space and ventricular cavities


where is the CSF reabsorbed

CSF is reabsorbed largely by the arachnoid granulations that project into the superior sagittal dural venous sinus and by small pial veins of the brain and spinal cord


how does the CSF flow (direction)

choroid plexus of lateral ventricles --> interventricular foramen of Monro --> 3rd ventricle --> narrow cerebral aqueduct of Sylvius --> 4th ventricle --> spinal canal, or through openings (lateral and median apertures) to access the subarachnoid space


name the meninges

dura mater
arachnoid mater
pia mater


how is the ANS divided

sympathetic and parasympathetic


is the ANS a two-neuron system?


the ANS is a 2 neuron system with a preganglionic neuron in the CNS that sends its axon into a peripheral nerve to synapse on a postganglionic neuron in a perihperal autonomic ganglion. The postganglionic neuron then sends its axon to the target.


what is another name for the sympathetic division of the ANS and why

AKA: thoracolumbar division
- its preganglion neurons are found only in the T1-L2 spinal cord levels
- its preganglion neurons lie within the intermediolateral gray matter of the spinal cord in the 14 segments defined above


effects of the sympathetic system

the sympathetic system acts globally throughout the body to mobilize it in "fright-flight-fight" situations

eye: dilates pupil
lacrimal glands: reduced secretion slightly (vasoconstriction)
skin: causes goose bumps (arrector pili muscle contraction)
sweat glands: increases secretion
peripheral vessels: causes vasoconstriction
heart: increases heart rate and force of contraction
coronary arteries: assists in vasodilation
lungs: assists in bronchodilation and reduced secretion
digestive tract: decreases peristalsis, contracts vasoconstriction to shunt blood elsewhere
liver: causes glycogen breakdown, glucose synthesis and release
salivary glands: reduces and thickens secretion via vasoconstriction
genital system: causes ejaculation and orgasm, and remission of erection.
urinary system: decreases urine production via vasoconstriction. constricts male internal urethral sphincter muscle
adrenal medulla: increases secretion of epinephrine or norepinephrine


is the parasympathetic division of the ANS a two-neuron system?


with its preganglionic neuron in the CNS and postganglionic neuron in a peripheral ganglion.


how is the parasympathetic division also known as and why

it is also known as the craniosacral division because:
- its preganglionic neurons are found in cranial nerves III, VII, IX and X, and in the sacral spinal cords at levels S2-S4
- its preganglionic neurons reside in the four cranial nuclei associated with the four cranial nerves listed previously, or in the lateral gray matter of the sacral spinal cord at levels S2-S4


what is the neurotransmitter in all parasympathetic synapses



what innervates the vascular smooth muscle, arrector pili muscles of the skin, and sweat glands

they are all innervated by the sympathetic nervous system because the sympathetic axons pass into the limbs, but the parasympathetic axons don't.


general functions of the parasympathetic system

the parasympathetic system is concerned with feeding and sexual arousal and acts more slowly and focally than the sympathetic system.

eyes: constricts pupil
ciliary body: constricts muscle for accommodation (near vision)
lacrimal glands: increases secretion
heart: decreases heart rate and force of contraction
coronary arteries: causes vasoconstriction with reduced metabolic demand
lungs: causes bronchoconstriction and increases secretion
digestive tract: increases peristalsis, increases secretion, inhibits internal anal sphincter for defecation
liver: aids glycogen synthesis and storage
salivary glands: increases secretion
genital system: promotes engorgement of erectile tissues
urinary system: contracts bladder (detrusor muscle) for urination, inhibits contraction of internal urethral sphincter, increase urine production


what regulates the ANS



what is the enteric nervous system

the enteric nervous system is linked to the sympathetic and parasympathetic divisions of the ANS, and these are required for optimal regulation of bowel secretion, absorption, and motility.


what does the ANS connection to the enteric nervous system include?

- Vagal parasympathetic input to the esophagus, stomach, small intestine, and proximal half of the colon
- S2 - S4 parasympathetic input via pelvic splanchnic nerves to the distal half of the colon and to the rectum
- sympathetic input from thoracic splanchnic nerves to the distal half of the colon and to the rectum
- sympathetic input from lumbar splanchnic nerves (LI-L2) to the distal half of the colon and to the rectum


what kind of functional components can a cranial nerve possess

general: same general gunctions as spinal nerves
special: functions found only in cranial nerves
afferent: sensory functions
efferent: motor functions
visceral: related to smooth muscle and glands
somatic: related to skin and skeletal muscle

GSA = general somatic afferents, meaning it contains nerve fibers that are sensory from the skin


what is CN I and what is its functional component

olfactory nerve = SVA (special sense of smell)


what is CN II and what is its functional component

optic nerve = SSA (special sense of sight)


what is CN III and what is its functional component

oculomotor nerve (motor ocular comun)
- GSE (motor to extraocular muscles)
- GVE (parasympathetic to smooth muscle in the eye)


what muscles does the CN III inervate and what do they do

levator palpebrae superioris: elevates upper eyelid
superior rectus: elevates, adducts, and rotates eyeball medially
inferior rectus: depresses, adducts, and rotates eyeball medially
medial rectus: adducts eyebal
inferior oblique: laterally rotates, elevates, and abducts eyeball


what is CN IV and what is its functional component

Trochlear nerve (patetico)
- GSE (motor to 1 extraocular muscle [medial rectus; adducts eyeballs)


what is CN V and what is its functional component

trigeminal nerve
- V1 and V2 are sensory
- V3 is both motor to skeletal muscle and sensory

- GSA (sensory to face, orbit, nose, anterior tongue)
- SVE (motor to skeletal muscles)


what is CN VI and what is its functional component

Abducens nerve (motor ocular externo)
- GSE (motor to 1 extraocular muscle [lateral rectus; abducts eyeball])


what is CN VII and what is its functional component

Facial nerve
- GSA (sensory to skin of ear)
- SVA (special sense of tase - posterior tongue)
- GVE (motor to glands; salivary, nasal, lacrimal)
- SVE (motor to facial muscles)


what is CN VIII and what is its functional component

Vestibulocochlear nerve (auditivo)
- SSA (special sense of hearing and balance)


what is CN IX and what is its functional component

Glossopharyngeal nerve
- GSA (sensory to posterior tongue)
- SVA (special sense of tase - posterior tongue)
- GVA (sensory from middle ear, pharynx, carotid body, and sinus)
- GVE (motor to parotid gland)
- SVE (motor to 1 muscle of pharynx)


what is CN X and what is its functional component

Vagus nerge
- GSA (sensory to external ear)
- SVA (special sense of taste, epiglottis)
- GVA ( motor to thoracis and abdominal organs)
- SVE (motor to muscles of pharynx/larynx)


what is CN XI and what is its functional component

Spinal accessory nerve
- SVE (motor to 2 muscles)


what is CN XII and what is its functional component

Hypoglossal nerve
- GSE (motor to tongue muscles)