Anatomy and Physiology Exam 4

Kirkwood Anatomy and Physiology 1

List three primary brain vesicles that develop at around 3-4 weeks gestation

-Prosencephalon, mesencephalon, rhombencephalon

What do telencephalon, diencephalon and mesencephalon form?

cerebrum, thalamus, midbrain

What do metencephalon and myelencephalon form?

pons and cerebellum, medulla oblongata

Three functions of the cranial meninges

covers/protects CNS, circulate CSF, enclose and protect blood vessels that supply CNS

Pia mater

-Contains capillaries for the brain,

Arachnoid mater

Circulates CSF, allowed by the subarachnoid space

Dura mater

Separates into two thick layers to allow for blood circulation

CSF filled cavities in the brain lined by ependymal cells

Ventricles

Four ventricles in the brain

Lateral, third, 4th

Septum pellucidum

Separates the two lateral ventricles

What forms the CSF

Choroid Plexus

Three functions of the CSF?

buoyancy (brain floats in CSF), protection, environmental stability (transports nutrients and chemical messengers)

Denied access across the blood brain barrier

metabolic wastes, proteins, toxins, most drugs, K+, non-essential amino acids

Allowed access across the blood brain barrier

Fat-soluble substances, alcohol, nicotine, anesthetics

What makes the capillaries in the blood brain barrier special

exceptionally impermeable tight junctions

White vs. Gray matter

White: regions with brain and spinal cord, w/ dense collections of myelinated axons (lipid)

Gray: neuron - cell bodies and nonmyelinated. “grey”- dark nuclei and chromatophilic axons

What fissure separates cerebrum and cerebellum

transverse

Functions of the frontal and parietal lobes?

Motor control, decision making, communication, personality (FRONTAL)

General sensory function, equilibrium

Functions of the occipital, temporal, and insula

vision, visual memories (OCCIPITAL)

hearing and smell (TEMPORAL)

Memory and taste (INSULA)

What separates frontal and parietal lobes?

central sulcrus

primary motor area and functions

precentral gyrus - controls voluntary muscle contraction

primary somatosensory area, function, and a few areas within

postcentral gyrus - receive impulses from skin and proprioceptors

Wernicke’s area, primary olfactory, primary auditory

What color brain matter composes the cerebral cortex?

Grey, superficial

Function of association areas in cerebral cortex

Memory, emotion, reasoning, personality

Ability to read, write, speak, calculate, remember, plan, imagine

Function of premotor cortex

helps plan movements, control learned motor skills

Brocha’s area

functional region of the brain located in only the left hemisphere and concerned with speech

Frontal eye field

Located near the premotor cortex and controls voluntary eye movement

Definition of association, commissural, projection

Association- connect different parts of the same hemisphere

Commissural- connect gray matter between hemispheres

Projection- connect hemispheres with lower brain or spinal cord

Location and role of cerebral nuclei

deep in cerebrum, influence movement

Which region of the diencephalon contains the pineal gland and habenuclar nuclei?

epithalamus

Role of the pineal gland and habenular nuclei?

Pineal- secretes melatonin to regulate sleep/wake cycle

Habenuclar- relay signals from limbic to midbrain, visceral and emotional responses to odor

Function of thalamus

Relay station for information coming into the cerebral cortex after sorting and editing

Function of the hypothalamus

Controls ANS, endocrine, food/water intake

Regulation of body temp, sleep/wake cycles

Stalks that connects the hypothalamus to pituitary gland

Infundibulum

Role of the brainstem, what structures compose of it?

Reflex, automatic body functions

Medulla oblongata, pons, midbrain

Cardiac center of the medulla oblongata, vasomotor centers of the medulla oblongata

adjusts force/rate of heart, generates respiratory rhythm and controls depth of breathing

Medullar respiratory center

adjusts blood vessels diameter to regulate pressure

Features of the Pons and the definitions

Middle cerebellar peduncles- transverse axons connecting pons to cerebellum

Pontine respiratory center- regulate skeletal muscles of breathing

Superior olivary nuclei - sound localization

Two components of the corpora quadrigemina and their functions

Superior colliculi- visual reflex centers

Inferior colliculi- auditory relay centers

Function of substantia nigra

Help control subconscious muscle activities

Houses neurons producing dopamine

Functions of the cerebellum

Coordinated skeletal muscles, compares cerebral cortex signal to proprioceptors (vision, equilibrium) stores memory, plays a role in cognition/language

Role of vermis in cerebellum

Receives sensory signals regarding torso & balance

Role of the lobes in cerebellum

controls subconscious aspects of movement

The fibers of the cerebellum function as

ipsilateral

Arbor vitae

Transmits sensory and motor information between cerebral cortex and deep cerebellar nuclei

Limbic system: definitions of fornix, amygdaloid body, cingulate gyrus, hippocampus

Fornix- fiber tract that links limbic system regions

Amygdaloid- asseses danger, and elicits fear response

Cingulate gyrus- emotional gestures, resolves mental conflict

Hippocampus- memory

Role of limbic system

Emotions

Memory, emotion, assessing danger

Role of reticular formation

Regulate muscle tone

role of RAS

maintain consciousness - active during awakening

Is cortical or brain stem activity decreased during sleep?

CORTICAL

What activity results in wakefulness

RAS levels increase

The four types of memory

Declarative- names

Procedural- Playing piano

Motor- riding a bike

Emotional - experiences linked to emotion

Short vs. long term

Short- temporary holding

Long-term - limitless capacity

Four factors that affect the transition from short to long term memory

-rehersal, emotional state, association, automation

Role of Wernicke’s area and motor speech area in language

W- interprets sentence, motor commands

M- involving muscles used for speech

How are cranial nerves named and numbered ?

Cranial nerves are named based on the structures they innervate and are numbered with Roman numerals according to their position from the front (rostral) to the back (caudal) of the brain.

List three functions of the nervous system

-Collect (sense changes in the environment)

-Process and evaluate (analyze, store, make decisions on stimuli)

-Initiate response (activate effectors)

Sensory and motor neurons are also known as

afferent, efferent neurons

Components and function of the CNS

Brain and spinal cord, integration and control center

Components and function of the PNS

Link body to CNS, nerves and ganglia

(spinal nerves- to and from spinal cord)

(cranial nerves- to and from brain)

Three divisions of the PNS

somatic (SNS), automatic (ANS), enteric (ENS)

ANS, ENS, and SNS definitions?

ANS- sensory impulses from visceral organs to CNS, CNS to smooth/cardiac muscle (sympathetic and parasympathetic)

ENS- involuntary sensory and motor neurons (control GI tract) -independent from ANS and CNS

SNS- sensory impulses from head, limbs, special sense s to CNS, CNS to skeletal

Which division of the PNS can be divided into sympathetic and parasympathetic

ANS

Difference between the sensory and motor nervous system?

Steps in the process

Sensory- detects stimuli and transmits information from receptors to CNS

Motor- initiates and transmits information from CNS to effectors

Nerve fibers

Composed of bundles of axons, connective tissue, and vasculature.

Three layers of connective tissue in a nerve from most deep to most superficial

Endoneurium, Perineurium, Epineurium

Nucleus (CNS) and Ganglia (PNS)

cluster of cell bodies that causes a bulge in a nerve

Neuroglia

glial cells that support, nurture, and protect neurons

Neurons (nerve cells)

excitable cells that transmit electrical signal

Four features of a neuron

Last a lifetime, high metabolic rate, capacity to produce action potentials, highly specialized cells that conduct impulses

Soma - function

Cell body, NT made here, then passed down the axon-to-axon terminal

Chromatophilic substance

The rough ER and free ribosomes for protein synthesis, growth, and repair

Dendrite and Axons

Dendrites- convey incoming messages toward cell body as graded potentials

Axons- impulse generator (info away from the cell body)

Axon terminal

Secretes NT into extracellular space

Nodes of Ranvier

Rich in ion channels, aids in how quick signals pass

A collection of axons with a common destination is a

CNS- tract

PNS- nerve

Where are unipolar, bipolar, and multipolar neurons found?

Unipolar- Sensory (PNS)

Bipolar- Sensory (retina, cochlear, olfactory)

Multipolar- Motor (CNS)

What direction do sensory/afferent neurons transmit information?

Sensory receptors to CNS

What direction do motor/efferent neurons transmit information?

CNS to effector organs

What direction do interneurons transmit information?

Between motor and sensory neurons - shuttle signals through CNS pathways

How many axons does an oligodendrocyte wrap around? How about neurolemmocyte?

Multiple, one

What are two functions of the myelin sheath?

Protects and electrically insulates the axons

Increases the speed of neuronal transmission along axon

In order for an action potential to occur, what needs to happen to the ions across a membrane?

A flow of ions is necessary, for there to be a change in the RMP (ACTION POTENTIAL) Change in concentrations across membrane

What is the difference between a leak and a gated ion channel?

Leak- continuous diffusion of ion along concentration gradient

Gated- open & close in response to a stimuli

Match the following types of gated ion channels to their stimulus.

Ligand

Voltage

Mechanical

Light

Ligand- neurotransmitter

Voltage-gated- Change in membrane potential

Mechanically-gated- Vibration

Light-gated - photoreceptor

Three stages of ligand-gated channel activity

1. Resting state - no chemical signal, ion channel remains closed.

2. Activation state- a ligand (NT in this case) binds to receptor site, opening the protein activation gate

3. Inactivatation state- Signal is terminated, (ligand disassociates from receptor)

Is a neuron more positive or negative outside the cell? Inside the cell?

Inside, more negative. Outside, more positive

To be ________________________ is to be not actively conducting a nerve impulse but electrically charged and ready for an impulse.

polarized

What conditions result in the resting membrane potential?

Concentrations of ions different outside and inside.

Membrane permeability differs for Na+ and K+ (K+ is 25x more permeable)

Which ions dominate the extracellular matrix at rest?Which ions dominate the intracellular matrix at rest?

ECF- Na+ and Cl-

ICF- K+ and Pi

Is the membrane more permeable to Na+ or K+? What effect does this have on the membrane potential?

K+, 25x more permeable. Causes more negativity on the inside.

The sodium-potassium pump moves ____ Na+ out for every ____ K+ in.

3 Na+ out for every 2 K+ in

What two actions result in changing the RMP?

Graded potentials

Potentials that are incoming signals operating over short distances that fizzle quickly. (local RMP changes)

Action potentials

occur when threshold is reached and are long-distance signals over the full length of the axon.

An action potential is_______ which means…

Propagating, rapid; it will only fire if that threshold is reached

The threshold for a neuronal action potential to fire is _________ !!!!!!!

-55mV

Refractory period, a neuron can or cannot generate another AP

CANNOT

Purpose of the refractory period

Ensures AP only moves one way, ensuring orderly transmission