Virginia Tech BMSP 2135 RAT 18

homeostasis

Maintenance of a relatively stable internal environment in the face of ever-changing conditions

Nervous and endocrine systems

What two systems in the body are key for maintaining homeostasis?

nervous system

Which system to maintain homeostasis works more quickly?

certain nuclei of the brainstem reticular formation, hypothalamus

Within the CNS, which two structures are key in maintaining homeostasis?

ANS

What system is largely responsible for homeostasis of vital functions such as heart rate, blood pressure, and digestion?

hypothalamus

What part of the CNS acts as a "boss" of the ANS?

hypothalamus

Where is the thermostat located in the body?

neurons in certain hypothalamic nuclei

What structure initiates changes to bring temperature down if it increases above normal?

hypothalamus

What structure in the brain helps regulate feeding?

hypothalamus

a potential anatomical explanation for feeling "Hangry" (angry when hungry) is that the same area of the __________________ that mediates hunger also mediates aggression and rage

sleep

__________ = a reversible and normal suspension of consciousness; the most fundamental, yet mysterious process carried out my humans and most animals; we are still unsure of the 'why' behind this process

survival

Sleep seems to serve an energy restoration function, allowing the brain to replenish its glycogen supply; however, if there are psychological reasons why we sleep, they remain elusive.

Nonetheless, it is clearly required for our ___________; sleep deprivation may cause imbalances in temperature homeostasis, weight loss, a decrease in cognitive abilities, hallucinations, and even death.

circadian rhythm

a biological process that follows a set pattern over the 24-hour day; we spend a period of the 24-hour cycle awake and another period of the cycle asleep

biological clock

the circadian rhythm is controlled by our own hypothalamic "____________ __________," which causes changes in the level of wakefulness in response to day and night cycles

melatonin

What hormone is released from the pineal gland?

reticular formation

The ____________ _________________ lowers the rate at which signals are sent from the thalamus to the cerebral cortex (the gateway is closed, so to speak)

nuclei of the reticular formation

melatonin depresses the activity of which structure?

cognition

the mental functions that include processing and responding to complex external stimuli, recognizing related stimuli, processing internal stimuli, and planning appropriate responses to stimuli

association areas of the cerebral cortex

what conducts cognition?

prefrontal cortex

Which area is largely responsible for the cognition that results in a person's character or personality?

cerebral lateralization

Many of the cognitive functions we just discussed are unequally represented in the right and left hemispheres, a phenomenon called _____________ ___________________

division of labor

cerebral lateralization

- The idea that certain cognitive functions are lateralized has led to the unfortunate misconception by the public that one hemisphere is "dominant" over the other, and that people can be "right-brained" or "left-brained."

- What cerebral lateralization actually represents is a _________ ____ ________ of sorts between the hemispheres—it is how our brains make the most use out of a limited amount of space.

emotional functions, attention, facial recognition, language-related recognition

Name four functions that are largely lateralized.

left frontal cortex

cerebral lateralization

emotional functions: this area of the cerebrum is responsible for positive emotions (happiness for example)

right frontal cortex

cerebral lateralization

emotional functions: this area of the cerebrum is responsible for negative emotions (anger & fear for example)

right parietal cortex

cerebral lateralization

this area of the cerebrum is responsible for attention

right temporal cortex

cerebral lateralization

this area of the cerebrum is responsible for facial recognition

left temporal cortex

cerebral lateralization

this area of the cerebrum is responsible for language-related recognition

Broca's area

responsible for the production of language, including the planning and ordering of words with proper grammar and syntax

Wernicke's area

responsible for understanding language and linking a word with its correct symbolic meaning

declarative (fact) memory

the memory of things that are readily available to consciousness that could, in principle, be expressed aloud

declarative

Examples of _______________ memory are a phone number, a quote, or the pathway of the corticospinal tracts.

nondeclarative memory

The memory of things that are largely procedural or skill-based; tends to include skills and associations that are largely subconscious.

Nondeclarative

____________________ memory can be exemplified by how to enter the phone number on a phone, how to move your mouth to speak the quote, and how to read this chapter.

consolidation

the term for the process of converting immediate and working memory into long-term memory

hippocampus

What brain structure is critical for forming new declarative memories?

basal nuclei

unlike forming declarative memories, which requires the hippocampus, forming nondeclarative memories requires the motor cortices, the cerebellum, and the __________ __________

relay station, processing station

what are the 2 primary roles of the spinal cord?

brain

2 primary roles of the spinal cord

relay station

- the spinal cord acts as a relay station and an intermediate point between the body and the _________; in fact, it is the only means by which the _________ can communicate with most of the body below the head and neck.

- it receives outgoing stimuli from the __________ and sends them to the rest of the body; it also receives incoming stimuli from the body and sends them to the ___________.

spinal reflexes

2 primary roles of the spinal cord

processing station

- although the spinal cord cannot perform the higher functions characteristic of the brain, it does do some integration and processing.

- in fact, certain activities called ________ ___________ can be carried out by the spinal cord alone, without influence from the brain

meninges

The ____________ of the spinal cord are continuous with that of the brain; however, there are some differences.

dura mater

differences between the meninges of the spinal cord and brain

1. The spinal meninges are similar in structure to those of the brain except for the ________ __________, which lacks a periosteal layer and consists only of a meningeal layer.

vertebral cavity

differences between the meninges of the spinal cord and brain

2. Also, the spinal pia plays a role that the cranial pia does not—it helps to anchor the spinal cord in the ____________ ____________.

epidural space

differences between the meninges of the spinal cord and brain

3. the spinal cord lacks a periosteal dura, so an _________ ____________ exists between the meningeal dura and the walls of the vertebral foramina.

epidural space

fat-filled space between the spinal dura mater and the internal surface of the vertebral cavity; filled with veins and adipose tissue, which helps to cushion and protect the spinal cord

CSF

Like the subarachnoid space around the brain, the spinal subarachnoid space lies between the arachnoid and pia and is filled with a very thin layer of _______. The area inferior to the base of the spinal cord contains a larger volume of _______, making it a useful place from which to take a sample if needed.

same answer for both

epidural anesthesia, lumbar punctures (spinal tap)

what are 2 medical procedures that access meningeal spaces?

motor or sensory impulses

medical procedures that access meningeal spaces

1. epidural anesthesia

- a local anesthetic medication is injected into the epidural space through an inserted needle.

- this procedure causes "numbing" of the nerves extending off the spinal cord below the level of the injection, which means they are unable to transmit what?.

- this type of anesthesia is commonly given to women during childbirth, as well as to both sexes during certain surgical procedures.

subarachnoid space

medical procedures that access meningeal spaces

2. lumbar punctures (spinal tap)

- during a lumbar puncture, a needle is inserted into the ______________ _________ and CSF is withdrawn for analysis

- lumbar punctures are performed to assess for several conditions, including meningitis, encephalitis, and multiple sclerosis.

between the fourth and fifth lumbar vertebrae to avoid any possibility of injuring the spinal cord

medical procedures that access meningeal spaces

during a lumbar punctures (spinal tap), where is the needle inserted and why?

foramen magnum

the bony structure that marks where the spinal cord and medulla oblongata meet

posterior median sulcus, anterior median fissure

What are the names of the indentations running along the front and the back of the spinal cord?

anterior median fissure

is the posterior median sulcus or anterior median fissure larger?

between the 1st and 2nd lumbar vertebrae

Where does the spinal cord end?

conus medullaris

cone-shaped terminal portion of the spinal cord between L1 and L2

filum terminale

What anchors the end of the spinal cord to the coccyx?

pia mater

filum terminale

- inferior continuation of the spinal _______ __________

- continues after the end of the spinal cord through the vertebral cavity and anchors into the 1st coccygeal vertebra

cervical enlargement, lumbar enlargement

The spinal cord bulges in two locations. What are the names of these bulges?

nerve roots

spinal cord bulges

the cervical and lumbar enlargements are important because the _______ ________ that fuse to form the spinal nerves serving the upper and lower limbs attach to these enlargements

cauda equina (resembles horse's tail)

large bundle of nerve roots given off at the terminal end of the spinal cord

central canal

What is the name of the channel that runs through the middle of the spinal cord?

CSF

what fluid is found in the central canal?

butterfly

The shape of the gray matter in the spinal cord is said to resemble what insect?

gray commissure

What is the name of the central gray matter that links the "wings" of the spinal gray matter together?

Neuron cell bodies, unmyelinated axons, dendrites, and neuroglia

what is gray matter composed of?

mostly myelinated axons

what is white matter composed of?

anterior horn

the _________ _______ is an area of gray matter in the spinal cord with neurons that are concerned with somatic motor functions (those of the skeletal muscles)

motor nerve fibers

The nerve roots attach spinal nerves to the spinal cord. What type of nerve fibers are found in the anterior root?

sensory nerve fibers

The nerve roots attach spinal nerves to the spinal cord. What types of nerve fibers are found in the posterior root?

sensory stimuli

What type of information is carried by ascending tracts in the spinal cord?

motor stimuli

What type of information is carried by descending tracts in the spinal cord?

action potentials

process by which sensory stimuli reach the brain

1. The stimulus is detected by neurons in the PNS and sent as sensory input to the CNS. These neurons initiate _______ _____________ that travel along their axons, usually to the spinal cord or the brainstem.

cerebral cortex

process by which sensory stimuli reach the brain

1. The stimulus is detected by neurons in the PNS and sent as sensory input to the CNS. These neurons initiate action potentials that travel along their axons, usually to the spinal cord or the brainstem.

2. In the CNS, the sensory input is sent to the _________ ___________ to be interpreted. The spinal cord or brainstem carries a signal generated in response to a stimulus to the ___________ __________, where it is interpreted.

perception

conscious awareness of the sensation

sensation

senses respond to stimuli

Special senses

_________ ________ are detected by special sense organs and include vision, hearing, equilibrium, smell, and taste

General senses

_______ ___________ are detected by sensory neurons in the skin, muscles, or walls of organs

general somatic senses, general visceral senses

general senses are divided into what 2 categories?

skin, muscle, joints

general somatic senses involve what?

internal organs

general visceral senses involve what?

first-order neuron

general somatic senses

this is the sensory neuron that detects the initial stimulus in the PNS

pseudounipolar

general somatic senses

Sensory first-order neurons are typically _________________ = neurons that have single short process that splits into 2 axons (no dendrites); act as sensory (afferent) neurons and are in the PNS associated with touch, pain, and vibration sensations

in the posterior horn of the spinal cord, or in the brainstem

general somatic senses

First order neurons synapse with second order neurons (interneuron) where?

thalamus

general somatic senses

The axons of second-order neurons generally synapse on third-order neurons, which are interneurons in the _____________

cerebral cortex

general somatic senses

after second-order neurons synapse with third-order neurons, the axons of third-order neurons deliver impulses to where?

primary somatosensory cortex

Third-order neurons end in the cortex. In particular, in the ___________ _________________ ________

postcentral gyrus

What is the name of the gyrus where the primary somatosensory cortex is located?

S1

What is the abbreviation for the primary somatosensory cortex?

right primary somatosensory cortex

Where would sensation arriving from the left knee be perceived in the brain?

certain areas have disproportionately more cortical area devoted to them

Why would the lips have a greater proportion of the gyrus dedicated to sensation than the arm?

homunculus

"little man"; shows what we would look like if body parts were proportionate in size to the relative sensitivity of those parts to areas of a certain brain region

Somatosensory association cortex (S2)

Where is a primary output for S1 axons?

nociception

What term denotes the perception of pain stimuli?

all species senses (vision, audition, gustation, vestibular sensation) EXCEPT olfaction

The thalamus acts as the "gateway" for which special senses?

occipital lobe

Where is the primary visual cortex located?

temporal lobe

In which lobe is the primary auditory cortex located?

olfaction

Which sense goes to the limbic system for initial processing? (This sense is particularly tied into emotion and memories)

motor areas of the cerebral cortex, basal nuclei, cerebellum, spinal cord

Name four components of the CNS that are critical for coordinated movement.

upper motor neurons, interneurons, lower motor neurons

Name the three types of neurons directly involved in eliciting a muscle contraction.

motor areas of the cerebral cortex

Where are the somas of upper motor neurons located?