Histology Quiz 4

Nervous tissue, skeletal muscle

cell body, nucleus, nucleolus, nissil body

satellite cells

What type of glial cells?

astrocytes

What type of glial cells?

Oligodendrocytes

What type of glial cells?

schwann cells

What type of glial cells?

Epnendymal cells

What type of glial cells?

Oligodendrocytes

myelin-producing cells that ensheathe axons for protection and to increase signaling efficiency

Astrocytes

abundant cells that support and protect neurons while also assisting with neuron function

Ependymal cells

cells that line the brain ventricles and spinal cord central canal; produce and circulate CSF

Microglia

migratory cells that act as immune cells in the CNS

contraction

key function of muscle tissue

skeletal, cardiac, smooth

3 types of muscle

move body parts, pump blood, drive involuntary movement

what is contraction used for?

quick, forceful and voluntary contractions

function of skeletal muscle

myofibrils

long protein fibers that dominate skeletal muscles cells

mitochondria, acidophilic

skeletal muscle is abundant in ____ making them ______

sarcomeres

\-basic contractile structure of skeletal muscle

\-repeating units that make up myofibrils

myofilaments

what are the proteins that make up sarcomeres called?

myosin

what are thick myofilaments made of?

actin

what are thin myofilaments made of?

A band

intensely staining region in sarcomere where thick and thin filaments overlap

I band

Near Z-discs, no overlap, only contains less dense thin filaments so this is the lightest staining region of the sarcomere

one z disc to the next

where does a sarcomere extend from

z-discs

where are sarcomeres anchored on each end?

acetylcholine

what crosses the neuromuscular junction to initiate contraction

inward towards M line

in contraction, myosin heads pivot to pull actin fibers _____

full

in skeletal muscle, every contraction is _____ meaning if a fiber contracts, then every sarcomere in that muscle fiber contracts

controlling how many muscle fibers are contracting

how do skeletal muscles control strength of contraction?

I band, A band, Z-disc

name these structures in skeletal muscle

fascicles

what are muscle fibers bundled into?

endomysium

\n Individual muscle fibers are surrounded by a thin ECM of \n reticular fibers called….

perimysium

\n Muscle fibers assemble into fascicles, what are fascicles bound together by?

epimysium

what binds multiple fascicles together to form an muscle?

myofilaments, sarcomere, myofibril, muscle fiber, fascicle, muscle

Organize from smallest unit to largest unit: \n – Myofibril \n – Fascicle \n – Myofilaments \n – Muscle fiber \n – Muscle

\-sarcomere

muscle fiber, fascicle, endomysium, perimysium

identify these muscle structures

black circle, red circle, small arrow, big arrow

myoglobin

what does red/slow fibers contain to give its color?

oxidative phosphorylation

what is the function of myoglobin?

red/slow

what type of muscle fiber would stain most intensely in an NADH or myosin ATPase antibody?

existing muscle fibers increase in size

how do skeletal muscles grow?

no, they have multiple nuclei

can muscle fibers divide? why?

undifferentiated satellite cells, myoblasts

\n During hypertrophy, _________ divide, differentiate into ______, and then fuse with existing muscle fibers to drive cell growth

atrophy

decrease in muscle size due to disuse or disease that can result in weakness or loss of function

cardiomyocytes

cardiac muscle cells

coordinated

what type of contractions do cardiac muscles generate?

collecting and analyzing info from environment/body, overseeing voluntary/involuntary actions

nervous system functions

neurons

–Cells that transmit, process, integrate, and respond to signals within the nervous system \n –Large cell bodies with large, euchromatic nuclei and often abundant ribosomes and RER in cytoplasm; long processes for signal reception and transmission

glial cells

Cells that support and protect neurons \n –Structure varies depending on specific function

information processing and message transmission/reception

function of neurons

synapses

sites of contact between adjacent cells in neuron for signal transmission

nissl bodies

clusters of ribosomes and RER – dense, basophilic cytoplasmic structures, common in neurons since they carry out such abundant protein production

dendrites

–Receive signals \n –Typically branched

axons

–Send signals \n –Often very long

ion channels

necessary for message transmission throughout the nervous system

6

how many total types of glial cells

oligodendrocytes, astrocytes, ependymal cells, microglia

what glial cells are found in the CNS?

schwann cells and satellite cells

what glial cells are found in the PNS?

myelin

Most axons in the nervous system are ensheathed in a lipid-based material called ______

protects axons and increases efficiency of nerve impulses

function of myelin

oligodendrocytes

\n -Produce myelin and ensheath axons within the CNS to protect axons and improve efficiency of signal transmission \n -have pale-staining cytoplasm due to abundant myelin

astrocytes

\-Provide metabolic support for neurons, as well as protecting, repairing damage, and assisting with neuron function \n •Very abundant throughout CNS \n •In H&E, only small basophilic cell body is apparent; with specialized stains, cellular processes are also apparent

ependymal cells

\-Line surfaces of brain ventricles and spinal cord central canal, \n where they produce CSF; also ciliated to circulate CSF \n •Columnar, ciliated cells resemble epithelial cells, but are not – note absence of basement membrane

microglia

\-Act as immune cells without the CNS; can clean up cellular debris, recognize cellular damage, and recognize pathogens \n •Relatively small and rare, so difficult to identify without \n specialized stains

schwann cells

\-Ensheath axons within nerves of PNS for protection and increased signal efficiency \n •Cells themselves have poorly stained, streaky cytoplasm due to abundant myelin

nodes of ranvier

Small gaps between adjacent Schwann cells

satellite cells

\-Support and protect neuronal cell bodies in ganglia \n •Small, round, basophilic cells surrounding neuronal cell \n bodies in ganglia

brain and spinal cord

what does the cns consist of

meninges

connective tissue that ensheaths entire cns

gray matter

\-Neuronal cell bodies and dendrites – not much myelin \n -Abundant astrocytes

\-more intensely stained, more nuclei, often organized into layers with large neuronal cell bodies

white matter

\-Bundles of myelinated axons \n -Abundant oligodendrocytes and astrocytes

\-stains more poorly (myelin); often ‘streaky’ in appearance due to parallel axonal tracks and myelin

ganglia and nerves

2 general types of structures in the PNS

ganglia

clusters of PNS neuronal cell bodies

nerves

bundled axons throughout the PNS

endoneurium

delicate layer of ECM that ensheaths each individual axon with its accompanying schwann cells

nerve fiber

consists of axon, schwann cell, and endoneurium

fascicle

bundle of nerve fibers and its surrounding perineurium

perineurium

layer of CT that hold multiple nerve fibers together

epineurium

holds fascicles together in larger nerves

cerebellar cortex

Outer layer of highly folded gray matter

cerebellar medulla

Inner layer of white matter

brain stem

Heart rate, breathing, sleeping, eating

cerebellum

Fine motor control; cognitive processing

cerebrum

\n Movement, sensory processing, language, learning and memory

molecular layer

small cortex layer, sparsely distributed neurons as well as the dendrites of Purkinje neurons

granular, purkinje, molecular

layers of the cerebellar cortex from closest to farthest from inner medulla

pyramidal neurons

Most identifiable neurons w/ distinctive triangular cell bodies

cerebellum

what part of the brain?

cerebrum

what part of the brain?

sensory, motor

in the spinal cord, dorsal “horns” of gray matter enriched in ____ neurons, while ventral “horns” are enriched in strikingly large ______ \n neurons

dura mater, arachnoid layer, pia mater

3 layers of meninges from exterior to interior

efferent

types of neurons like pyramidal that extend axons away from CNS towards body