ISF Histology Exam 3 (Review Slides; written text)

Cardiac muscle description (4)

Strong quick continuous involuntary contraction

Skeletal muscle descriptions (4)

Strong quick discontinuous voluntary contraction

Satellite cells (PNS)

Surround neuron cell bodies in PNS The function is similar to astrocytes of CNS

Type IV collagen is in the ________ ________ and Type VII Collagen is in the _____________ _________.

lamina densa; fibroreticular densa

What part of the nervous system does the golgi tendon organ (detecting tension) and muscle spindle (detecting stretch) relay information to?

CNS

What are the four major glial cells of the CNS and what are the two major glial cells of the PNS?

CNS - Oligodendrocytes - Astrocytes - Ependymal cells - Microglial cells PNS - Neurolemmocytes - Satellite cells

How do we synthesize serotonin (which can make melatonin)

Hydroxylation and decarboxylation of tryptophan

What is myomesin?

Myosin-binding protein in the M line that holds the thick filaments in place

H&E Stain of neuronal nucleus/nucleolus, glial nuclei and Neuropil

N= neuronal cell bodies; G = glia cells; Np = neuropil

What structures are smooth muscle lacking insofar as thin filaments are concerned?

NO Troponin, NO T-Tubules, but has Calmodulin (that Ca binds to) There is calcium release externally or internally based on signal to the smooth muscle

Is there a banding patten in cardiac muscle?

No, no striations

Does smooth muscle have a triad or diad?

No, smooth muscle has neither

Are bipolar neurons motor neurons?

No. Bipolar neurons are relatively rare. They are sensory neurons found in olfactory epithelium, the retina of the eye, and ganglia of the vestibulocochlear nerve.

What is in between myelin down an axon?

Nodes of Ranvier

Neurolemma

the outermost nucleated cytoplasmic layer of Schwann cells that surrounds the axon of the neuron. It forms the outermost layer of the nerve fiber in the peripheral nervous system.

Is it true that muscle spindles (that are on the inside of extrafusal fibers) contain a lot of nuclei packed into the intrafusal fibers?

True

What fiber inside the endomysium of smooth muscle helps hold the individual cells together? These fibers help summate force together

reticulin fibers

We find bipolar neurons in the (which body part)?

retina

example of merocrine gland

salivary and sweat gland

Myosin's role:

the binding of myosin to actin filaments, allowing myosin to function as a motor that drives filament sliding (contraction)

Are muscle fibers elongated multinuclear cells?

yes

Can mitochondria be viewed in the i bands of TEM striated muscle?

yes

Is epimysium (DICT) continuous with fascia and the tendon binding muscle to bone?

yes

Tissue space and how molecules move in skin (WATCH SKIN VIDEO FROM CRASH COURSE)

KNOW

What is the epimysium made of?

dense irregular connective tissue (DICT)

What moves stuff from the synapse to the cell body of neurons?

kinesin and dynein

Neurolemmocytes (Schwann cells)

myelinate axons in the PNS

What's faster, myelinated or unmyelinated?

myelinated

Each muscle fiber contains several parallel bundles called ___________.

myofibrils

Where do we find ependymal cells?

near central canal of spinal cord

What does change during contraction of the sarcomere?

H zone, I band, and sarcomere shortens

ependymal cells

produce and circulate cerebrospinal fluid

What allows cytoplasm to move up and down the myelin sheaths?

Schmidt-Lanterman clefts (gaps from imperfect wrapping of myelin)

The region of intercalated discs of cardiac muscle has three components, what are they?

Fascia adherens maculae adherens (desmosomes) gap junctions

* A band = (1.5 micrometers) + (i-band = 1.0 micrometer) * What is the length of the sarcomere at rest?

* A band = (1.5 micrometers) + (i-band = 1.0 micrometer) 2.5 micrometers ((1/2 of i-band) x2) + A-band = 2.5 micrometers --> A-band stays constant

neurofibril nodes

"nodes of RANVIER" gaps between neurolemmocytes

What is the ratio of glia to neurons?

10:1

Perineurium

2-6 layers of tightly packed fibroblast-like cells

2% of skeletal muscle is mitochondria but ____% of cardiac myocyte is mitochondria.

40%

Myosin head, after inorganic phosphate breaks from ADP and power stroke initiates, will swivel back on it's tail axis to ______ degrees.

45

Myosin head is at a(n) ____ degree angle without ATP and with ATP it cocks back to a(n) ____ degree angle. This is the process of going from position one to position two.

45; 90

intercalated discs of cardiac muscle A, B, or C

A

multipolar neuron

A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system. Most common

What is the one major neurotransmitter that cholinergic neurons use

Acetylcholine

What are dense bodies in smooth muscle?

An attachment site for actin to the plasma membrane: anchor for contraction. - Contains alpha-actinin. (intermediate filaments also attach)

What is myasthenia gravis?

An autoimmune disorder that involves circulating antibodies against protein of acetylcholine receptors.

What is titin and what does it do?

Anchors thick filaminets (myosin) to Z line (similar to alpha-actinin's job for thin filaments)

Nuerolemmocytes

Another word for Schwann cells

CFS is in

Arachnoid space

What is a tendon?

Attaches muscle to bone

Melanin formation

Begins in the epidermis Melanin is a pigment that is produced by cells known as melanocytes in the skin of most animals. It comes in two basic forms: eumelanin (brownish color) and pheomelanin (reddish-brown color). The production of melanin is affected by: - UV exposure, - genetic make-up, - size of melanocytes, - disease conditions.

Where are arteries and veins located in skeletal muscle?

Between muscle fascicles (surrounded by perimysium)

Where are arterioles and venuoles located in skeletal muscle?

Between muscle fibers (surrounded by endomysium)

fascia adherens

Binds adjacent myocytes together in cardiac muscle. Broad band in which the actin of the thin myofilaments is anchored to the plasma membrane. Desmosome-like connections; provide strength.

ramification

Branching; A branching point; A development or consequence resulting from a course of action

What does CSF (found in Arachnoid mater) do?

CSF bathes and cushions the brain and spinal chord within their bony confines during rapid body movements.

What is a calcium induced calcium release?

Calcium induced calcium release is when calcium is able enter the sarcoplasm via DHP to bind to and activate Ry and cause calcium release into the sarcoplasm.

Why do we need calcium in our diet?

Calcium is a mineral that is necessary for life. --> In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. --> About 99% of the calcium in our bodies is in our bones and teeth. --> Our bodies cannot produce its own calcium.

Cardiac muscle defintion

Cardiac muscle has cross-striations and is composed of elongated, often branched cells bound to one another at structures called intercalated discs. Contraction is involuntary, vigorous and rhythmic.

stratum corneum

Cells are dead; represented only by flat membranous sacs filled with keratin. Glycolipids in extracellular space.

Purkinje cells are found in the _________ and Pyrimidal cells are found in the _______ _______.

Cerebellum; Cerebral cortex

Full explanation of what makes CSF:

Cerebrospinal fluid (CSF) is a clear, colorless body fluid found in the brain and spinal cord. It is produced by the specialized ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations.

What are the Three parts of the CNS?

Cerebrum Cerebellum Spinal Cord

Spiral fractures (spinning and jerking a child's arm), fluid in the subdural space (from being hit) and subdermal hematomas (from being hit with there soft skulls) are good indicators of:

Child abuse

What make acetylcholine?

Choline acetyltransferase

axon hillock

Cone shaped region of an axon where the axon is connected to the the neuronal cell body.

Perimysium

Connective tissue surrounding a fascicles that contain bundles of muscle fibers

Endomysium

Connective tissue surrounding and separating muscle fibers

What's the white stuff in between the cross section here

Connective tissue. That myocytes of cardiac muscle need something to anchor onto. Punctated appearance and not quite and perfect and polygonally shaped as skeletal muscle cross section. CT = connective tissue; V = venule; A = arteriole; C = capillaries; N = cardiac muscle cell nuclei.

Skeletal muscle definition

Contains bundles of very long multi-nucleated cels with cross-striations. Their contraction is quick, forceful, and usually under voluntary control.

What is the function of a myofibrils in a muscle cell (muscle fiber)?

Contraction

What are the Three parts to the PNS?

Cranial Nerves Spinal Nerves Ganglia

What is a Schmidt-Lanterman cleft?

Crease in myelin sheath from neurolemmacyte (Schwann Cell in PNS), wrapping the nerve over and over

Langerhans cells

Dendritic cells (antigen-presenting immune cells; macrophage-like cells) of the skin, and contain organelles called Birbeck granules. They are present in all layers of the epidermis and are most prominent in the stratum spinosum.

Maculae adherens (desmosomes)

Desmosomes connect two cells together. - A desmosome is also known as a spot desmosome or macula adherens (macula = latin for spot), because it is circular or spot like in outline, and not belt- or band shaped like adherens junctions. ... Also notice the intermediate filaments running from the desmosome into the cytoplasm.

Three major catecholamines

Dopamine, Norepinephrine, Epinephrine

Posterior is ventral or dorsal?

Dorsal

Unipolar (pseudounipolar) description and example

Dorsal root ganglion single, short process that has two branches (all one axon), that goes to periphery in one process and CNS in the other direction

Some notes on Ependymal cells

Ependymal cells are epithelial-like cells that line the fluid-filled ventricles and central canal of the CNS. They have cilia and microvilli that extend from apical surfaces into the ventricle. Circulate CSF and monitor its contents. Ependymal cells have junctional complexes at apical ends, however, they lack a basal lamina. Basal ends are tapered and extend processes that branch and penetrate into adjacent neuropil.

Transverse tubules (T-tubules)

Extensions of sarcolemma Carry action potential deep into muscle fiber Transmit action potential through cell Allow entire muscle fiber to contract simultaneously Have same properties as sarcolemma conducting AP's Deep invaginations of the sarcolemma that extend into the sarcoplasm

inhibitory neurotransmitters

GABA

Which four neurotransmitters are active in the brain?

GABA Gly, Glu, Asp

Cells are most dense in the granular layer or molecular layer of the cerebellum (where we find purkinje fibers)

Granular layer

What do dendritic spines do for us?

Help us make new connections in our brains; allows for neuroplasticity

Nebulin

Holds F-actin strands together

What is tropomyosin and what does it do?

It is a double stranded protein that covers active sites on actin, preventing myosin from binding to actin when muscle fibers rest

What help ependymal cells stir around cerebral spinal fluid?

Large cilia on them

Neurolemmocytes can surround neuron without creating myelin wrapping. What do we lose from this AND what benefits do we still retain from the Schwann cells (Neurolemmocytes) surrounding the neuron?

Loss: - High speed conductance Retain: - Some protection

Check out, how it's punctuated but its very regular, unlike cardiac that is not perfectly shaped.

M = muscle fiber; BV = blood vessels (shown here are a small artery and vein); CT = connective tissue (perimysium surrounding muscle fascicles); N = nuclei of muscle cells; asterisks = examples of capillaries

What bisects the A band?

M line

What do microglial cells do?

Microglia migrate through the neuropil scanning for damaged cells and invading microorganisms

Microglial cells (CNS)

Mobile immune system cells within the CNS

Extensibility

Muscle can be stretched.

What are the black dots in this photo?

Muscle cells from the heart atrium show the presence of membrane-bound granules (G), mainly aggregated at the nuclear poles.

Excitability

Muscle is excited by nerves, i.e., electrical impulses

Contractility

Muscle shortens and generates force.

Structure and function of muscle spindle:

Muscle spindles have afferent sensory and efferent motor nerve fibers associated with the intrafusal fibers (modified muscle fibers).

Elasticity

Muscle will recoil from stretch.

Embyronic origin of melanocytes

Neural Crest origin

What are the two major glial cells of the PNS?

Neurolemmocytes Satellite cells

DHP receptor

Non-conducting calcium channels in the T-tubule membranes of skeletal muscle cells, which act as voltage sensors in excitation-contraction coupling that communicate with Ryanodine receptors

What makes myelin in CNS?

Oligodendrites

What are the four major glial cells of CNS?

Oligodendrocytes Astrocytes Ependymal cells Microglial cells

What happens in an inhibitory synapse?

Open anion channels --> anion enters cell --> membrane hyperpolarizes (more negative) --> harder to generate an AP

What happens in an excitatory synapse?

Open cation channels --> influx of cation --> local reversal of postsynaptic membrane voltage to threshold (depolarization) --> initiation of action potential (AP) --> generation of nerve impulse

What is a nerve cell body?

Perikaryon or Soma. Contains the nucleus and nucleolus, has well developed nissl-bodies (rough er), contains an axon hillock.

What structure provides the blood/nerve barrier?

Perineureum

Where are satellite cells found in muscle?

Periphery of muscle fibers

Ca in blood clotting

Platelet aggregation and fibrin formation both require the proteolytic enzyme thrombin. *** --> Clotting also requires: Calcium ions (Ca2+)(which is why blood banks use a chelating agent to bind the calcium in donated blood so the blood will not clot in the bag).

We should not have anything in the ____________ space of the meninges it's a "potential space."

Potential

What are skeletal muscle satellite cells?

Progenitor cells that remain adjacent to most fibers of differentiated skeletal muscle

Directly on the axon terminal, there is no myelin anymore but what makes myelin in the PNS covers the axon terminal. What is covering and providing some protection?

Schwann cells

Astrocytes

Provide structural support (blood brain barrier) and metabolic support for neurons.

What is the major neuron type found in Cerebellum?

Purkinje fibers

What cells has vast dendritic arbors?

Purkinje fibers (found in cerebellum)

What are the unique cells in the cerebral cortex?

Pyrimidal cells (type of neuron), surrounded by glial (like all neurons are) in the CNS

What are the glial cells of the PNS?

Schwann cells and satellite cells

Nissl substance

RER found in cell body and dendrites, but not axon of neurons.

What are Nissl bodies?

RER in neurons

Axial

Relating to head, neck, and trunk, the axis of the body

What fibers are interwoven into the basal lamina (that is superficial to sarcolemma)?

Reticular fibers

Pia mater *never* touches neuronal tissue, WHY?

Right under the Pia Mater is the Glia Limitans, which are the astrocytic end feet of Astrocytes

What is the enzyme name to get calcium back into sarcoplasmic reticulum?

SERCA, or sarco/endoplasmic reticulum Ca2+-ATPase, or SR Ca2+-ATPase, is a: - calcium ATPase

Is a Pacinian corpuscle nerve ending for motor or sensory?

Sensory

Neural Tissue OF SKIN

Sensory receptors (touch, pain, temperature)

Which muscle has bipolar heads on thick filaments and which muscle as *side polar heads* on thick filaments?

Skeletal muscle and smooth muscle respectively

Cross section of Meninges (membranes that cover the brain and spinal cord)

Skin of scalp Periosteum Bone of Skull (diploe) Dura mater Subdural space (potential space) Arachnoid mater (w/ trabeculae) Pia Mater

Between Dura Mater and Arachnoid Mater is the ________ space.

Subdural

What is the sarcolemma?

Surround muscle cell (muscle fiber); cell boundary

Confusing photo

T1 and T2 = presynaptic terminals (note that T2 is an axoaxonic synapse); D = dendrite

Do kerotinocytes synthesize: - Basal-lamina proteins - Hemidesmosomes - Lamina lucida - and Lamina densa TRUE or FALSE?

TRUE Keratinocytes synthesize basal-lamina proteins in culture. ...In culture, epidermal keratinocytes are able to produce hemidesmosomes, lamina lucida, and lamina densa. There is no evidence that cultured keratinocytes can produce sub-lamina densa fibrils. Biochemically, the lamina lucida contains two major glycoproteins.

Diploe (spongy bone)

The diploe is a soft and spongy material located between the inner table and the outer table (the inner and outer bony plates) of compact tissue, contains bone marrow and is called diploe zone.

Microtubules in neurons

The microtubules in neuronal axons are stable. These microtubules are positioned with + end toward the axon terminal. Motor proteins (kinesin and dynein) transport neurotransmitter-containing vesicles through the axon using microtubules as tracks.

Anterior horn is ventral or dorsal?

Ventral

Dynein motors running along microtubules inside neurons: (toward synapse or toward cell body)?

Toward cells body (toward nucleus)

Kinesin motors running along microtubules inside neurons: (toward synapse or toward cell body)?

Toward synapse

What is TEM in histology slides?

Transmission Electron Microscopy

Type IIa skeletal muscle fibers

Type IIa Fast, intermediate oxidative-glycolytic fibers (medium) Many mitochondria and high myoglobin content Contain large amounts of glycogen Utilize both oxidative metabolism and anaerobic glycolysis Intermediate between other fiber types in color and energy metabolism Adapted for rapid contractions and short bursts of activity Generate high peak muscle tension e.g. Sprinters, hockey players "Fast twitch, fatigue-resistant motor units"

Oligodendrocytes

Type of glial cell in the CNS that wrap axons in a myelin sheath.

What AA synthesizes the three catecholamines (dopamine, norepinephrine, and epinephrine)?

Tyrosine

What happens if we have too much CSF?

We have Arachnoid Villi that protrude into the Superior Sagittal Space and dump excess CSF (cerebral spinal fluid)

Do pyrimidal cells (in the cerebral cortex) have apical dendrites?

Yes

Do we find axons with myelin surrounded by endoneurium in bundles called facicles surrounded by perinereum with some blood vessels like arteries and veins just like in muscle?

Yes

In cross sectional histological slides, do we find the nuclei of cardiac cells be be directly in the center of the cell?

Yes

Is basal lamina superficial to the sarcolemma?

Yes

Nucleolus is inside of nucleus yes or no

Yes

Are there banding patterns in cardiac muscle?

Yes, it's striated

What bisects the I band?

Z line

Most abundant protein in eukaryotes

actin

Thin filaments are _____ filaments with one end bound to α-actinin in the Z disc.

actin

Myosin heads have two binding sites for ________ (thin filament) and ATP (which allow myosin to let go of thin filament)

actin; ATP

Which types of neurons use the three catecholamines neurotransmitters (Dopamine, Norepinephrine, Epinephrine?

adrenergic neurons

What is alpha-actinin?

anchors thin filaments (actin) to the Z line (similiar to titin's job for thick filaments)

Are ependymal cells cilia on the apical or basal membrane in the spinal cord (where they are located)?

apical membrane

Hemidesmosomes

attach epithelial cells to the basement membrane

axodendritic synapse

axon to dendrite spine

axosomatic synapse

axon to soma (cell body)

What are the three parts of endomysium?

basal lamina, reticular fibers and capillaries

type IV collagen: under the floor (BM)

basement membrane

Astrocytes (CNS) cover such a large portion of the blood vessels so it makes sense that they make up such a large portion of the _____ _____ _______ (BBB).

blood brain barrier

example of apocrine secretion

breast milk from mammary gland

fibronectin and laminin

cell adhesion proteins in ground substance; CT glue

What is the dorsal root ganglion?

cell bodies of sensory neurons

What is the soma?

cell body of a neuron

stratum basale

cells are actively mitotic stem cells; some newly formed cells become part of the more superficial layers

stratum granulosum

cells are flattened, organelles are deteriorating; cytoplasm full of lamellated granules (release lipids) and keratohyaline

Stratum spinosum

cells contain thick bundles of intermediate filaments made of pre-keratin

central canal of spinal cord

center of spinal cord which contains cerebrospinal fluid

Pyrimydal cells are multipolar cells of the _________ cortex

cerebral

What enzyme creates acetylcholine?

choline acetyltransferase; made from acetyl CoA and choline

Where is cerebral spinal fluid made?

choroid plexus

What releases calcium in the sarcoplasmic reticulum after a depolarization down the T-tubule?

cisternae of SR

terminal arborization

complex of branches at axon's distal end

Epimysium

covers the entire muscle

What do troponin and tropomyosin do?

create steric hinderance for myosin

A triad is a T-tubule and two terminal cisternae of the SR on either side. In cardiac muscle we call it a ______.

diad

example of unipolar neuron

dorsal root ganglion

Meninges

dura mater, arachnoid mater, pia mater

Epithelium OF SKIN

epidermis - stratified squamous epithelium, keratinized

Between the bones of the spinal cord and dura mater is the ____________ space.

epidural

cisternae

flattened membranous sacs

ground substance

fluid or semi-fluid portion of the matrix

Type VII collagen

forms anchoring fibril loops (around reticular fibers) that link to basement membrane

mast cells

found in the connective tissue of the dermis; respond to injury, infection, or allergy by producing and releasing substances, including heparin and histamine

Remember that Meissner corpuscles sense ______ touch and Pacinian corpuscles sense ______ touch)

gentle; course (pressure)

Half weight of brain is neurons and other half is _______

glia

excitatory neurotransmitters

glutamate

What do myelin sheaths do?

insulate and prevent leakage of charge; allows for saltitory conduction

Majority of neurons are

interneurons

Mojority of neurons are

interneurons

Sequestered definition

isolated and hidden away

The basal lamina of the skin is produced by

keratinocytes in the stratum basale

What is the A band?

length of myosin

What is a nerve fiber?

long axon

What is the role of actin?

makes up microfilaments and thin filament has + and - side

example of apocrine gland

mammary gland

Myelin in makes the axon a ________ effective capacitor

more

What are the 3 principle functions of skeletal muscle?

motion heat production posture (support)

Ventral horn is sensory or motor?

motor

In the CNS an oligodendrocyte will wrap _________ axonal sections. Leaving gaps inbetween the myelin wrapping called _______ ___ _________.

multiple; Nodes of Ranvier

What are capillaries supplying?

nutrition to muscle

example of holocrine secretion

oil produced from sebaceous glands

How many nuclei does cardiac muscle have?

one

How many nuclei does smooth muscle have?

one

bipolar neurons

one axon and one dendrite

What is the i band?

only actin

Is the dorsal root ganglion inside or outside the spinal cord?

outside

Macrophages

phagocytize foreign substances and help activate T cells

Dendrites

receive messages from other cells

SEM

scanning electron micrograph

example of holocrine gland

sebaceous (oil) glands

SSRIs

selective serotonin reuptake inhibitors

Dorsal horn is sensory or motor?

sensory

Which neurons use serotonin?

serotonergic

How many muscle actin around one myosin?

six

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone

example of merocrine secretion

sweat (from sweat glands) and saliva (from salivary glands)

Is the myosin head bound weakly or strongly to position two when it is cocked back at 90 degrees?

weakly

arachnoid mater

weblike middle layer of the three meninges

Lymphocytes

white blood cells

stretch receptors

works with kinesthetic senses; specialized nerve ending receptors that are attached to muscle fibers and sense if the muscle stretches and responds with contractions

What is tropomodulin?

- A protein which binds and caps the minus end of actin, regulating the length of actin filaments in muscle. - The protein functions by physically blocking the spontaneous dissociation of actin monomers from the minus end of the actin fiber.

What is C protein?

- A structural protein that is part of the thick filament - Is involved in holding the tails of myosin in a correct spatial arrangement

excitation-contraction coupling

- AP comes down axon. - Ca2+ is released into presynaptic terminal allows for exocytosis of - - - - Acetylcholine into the neuromuscular junction. - This causes a wave of depolarization. - Depolarization travels along the T-Tubules which are invaginating in the muscle. - So you have rapid conduction of that electrical impulse through the entire body of the muscle. - That electrical impulse comes down the T-Tubules, Voltage sensor proteins cause a release of Ca down that sarcoplasmic reticulum. - Once that Ca is released the inhibition that had been on the myosin binding sight on actin is released from Troponin binding TnC and moving tropomyosin out of the way. for myosin to bind to the binding site on actin.

What is a tendinocyte?

- An elongated cell with invisible cytoplasm and flattened, poorly-stained, nucleus. - It is found in the tendon and is positioned in a very regular pattern of rows between parallel bundles of collagen fibers. - It makes up the fibers and ground substance of the tendon.

Breakdown of the cross section of a spinal cord

- Dura mater - Subdural space - Arachnoid mater - Subarachnoid space - Sometimes you'll see Connective Tissue, Trabeculae - May start seeing some Blood Vessels - Eventually, you're at the Pia Mater - Then at the Anterior Median Fissure you'll see the Pia Mater invaginate into the white matter of the spinal cord.

Connective Tissue: in Dermis and Hypodermis OF SKIN

- Loose areolar just below the epithelium - Dense irregular below the areolar - Adipose in the hypodermis

neuron vs glial cells

- Neurons have TWO "processes" called axons and dendrites....glial cells have only ONE. - Neurons CAN generate action potentials...glial cells CANNOT. - However, glial cells do have a resting potential. Neurons HAVE synapses that use neurotransmitters...glial cells do NOT have chemical synapses.

Stratum lucidum (clear layer)

- Only in thick skin - Thin, translucent band superficial to the stratum granulosum, deep to stratum corneum - A few rows of flat, dead keratinocytes

endomysial capillary network

- Rich blood supply to muscles - Reflects the high metabolic demand - Wavy when the muscle fibers contract and stretched straight when the muscle extends - Are in between myofibrils

Type I skeletal muscle fibers

- Slow, red, oxidative fibers (small) - Many mitochondria and abundant myoglobin - Mostly oxidative phosphorylation - Low glycogen levels - Energy primarily from oxidative phosphorylation (aerobic) - Adapted for slow, continuous contractions over prolonged periods --> e.g. Postural muscles of the back/marathon runners "Slow twitch, fatigue-resistant motor units"

sarcoplasmic reticulum (SR)

- Specialized smooth endoplasmic reticulum, which stores, releases, and retrieves Ca++ - A specialized endoplasmic reticulum that regulates the calcium concentration in the cytosol of muscle cells. - Smooth ER that forms a network around each myofibril

What is the myotendinous junction?

- Tendons develop together with skeletal muscles and join muscles to the periosteum of bones. - The collagen fibers of a tendon (T) are continuous with those in the connective tissue layers around muscle fibers (M), forming a strong unit that allows muscle contraction to move the skeleton.

What is actin?

- Thin filament protein. - Twisted into a double helix of g-actin and appears like a double-stranded chain of pearls. Contains the myosin-binding site.

gap junctions in cardiac muscle

- electrically connect cardiac muscle cells; - concentrated in the intercalated discs; - regions where the plasma membranes of adjacent cells fuse together, with special proteins that form channels allowing ions to diffuse from one cell to the other

unipolar neuron

-single process leading away from the soma -sensory from skin and organs to spinal cord

What are the two ways smooth muscle cells hold together?

1) Gap junctions 2) Dense bodies in the cytoplasm

Describe skeletal muscle embryonic muscle development:

1) Mesenchymal myoblasts fuse, forming myotubes tubes with many nuclei. 2) Myotubes then further differentiate to form striated muscle fibers.

Fibrillar proteins: two types of this collagen 1) 2)

1) Osteoid in bone 2) Chondroid in cartilage

Astrocytes have _______________ feet that is part of the blood brain barrier. These __________ feet are going to be apart of/attach to the outside of the ____ ____ __ ___ ______ near the carpillary (blood supply) that is the blood brain barrier (BBB).

1) perivascular 2) cell body of the neauron

Glutamate synthesis

1. Glucose -‐-‐> Acetyl CoA -‐-‐> α-‐ketoglutarate via glycolysis and TCA cycle, respectively 2. α-ketoglutarate --> glutamate via transamination

--> A-band = (1.5 micrometers) + (i-band = 1.0 micrometer) 1) What is the length of the sarcomere if the sarcomere contracted 20% 2) What component of the sarcomere reduced in length during contraction?

1.5 stays the same * 2.5 - 20% = 2.0mM * 1.5 doesn't change, so i-bands went from 1.0 micrometer each to 0.5 micrometer each; 0.25 on each side of the A-band (that is constantly 1.5 micrometers; *Z line bisects the i-band). * THEREFORE: * 1.5 + 0.25 + 0.25 = 2.0mM

spinal nerves

31 pairs of nerves arising from the spinal cord

What embryonic cells are skeletal muscles formed by?

Myoblasts

What doesn't change during contraction of a sarcomere?

A band, M-Line

Thick filaments are bundles of myosin, which span the entire ___ ______ and are bound to proteins of the ___ ______ and to the Z line across the I bands by a very large protein called ______, w_hich has springlike domains

A band; M line; titin

Fibronectin

A glycoprotein that helps animal cells attach to the extracellular matrix.

motor unit

A motor neuron and all of the muscle fibers it innervates

Glycoproteins

A protein with one or more covalently attached carbohydrates.

integrin

A receptor protein built into the plasma membrane that interconnects the extracellular matrix and the cytoskeleton

Triad (sarcoplasmic reticulum)

A triad is the structure formed by a T tubule with sarcoplasmic reticulum (SR) on either side (known as terminal cisternae).

Desmosomes (anchoring junctions)

A type of cell junction in animal cells that functions like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor them in the cytoplasm. They attach muscle cells to each other in a muscle.

At the end of the power-stroke, what is released from the myosin head?

ADP

Why are there invaginations of the sarcolemma of the muscle fiber at the synaptic terminal?

Allows for increased receptor capacity of Acetylcholine receptors

How many connections can be made off one purkinje neuron from all of the dendritic arbors being given off

Around 200,000 connections

After dendrites receive message from other cells, where is the eletrical impulse carried down on the neuron?

Axon

Astrocytes (CNS or PNS?)

CNS

Which neurons form white and gray matter?

CNS myelinated neurons are called white matter, while non-myelinated CNS axons are called gray matter.

Cardiac myofibers differ from skeletal muscle fibers in what ways?

Cardiac myofibers are not one long tubes, they are individual myocytes connected end to end.

Four tissues of skin

Epithelium Connective Tissue (Dermis and Hypodermis) Muscle tissue Nerual Tissue

Cerebral Spinal Fluid (CSF)

Fluid, produced by ventricles, found within Spinal Cord and in covering surrounding CNS

Muscle Tissue OF SKIN

Found near hair follicles and in blood vessels (smooth)

hyaluronic acid

Hydrating fluids found in the skin; hydrophilic agent with water-binding properties.

pia mater

Innermost layer of the meninges

What kind of stain are the grey and white photos of skeletal muscle?

Instead of H&E staining that is pink and blue, it is "hematoxylin stain"

Keytruda function

KEYTRUDA is a monoclonal antibody that binds to the PD-1 receptor and blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2. >Upregulation of PD-1 ligands occurs in some tumors, and signaling through the PD-1 pathway can contribute to inhibition of active T-cell immune surveillance of tumors. >Binding of the PD-1 ligands, PD-L1 and PD-L2, to the PD-1 receptor found on T cells INHIBITS T-cell proliferation and cytokine production. >KEYTRUDA binds to the PD-1 receptor and releases PD-1 pathway-mediated inhibition of the immune response, including the antitumor immune response. ***Take Away*** - Keytruda is an antibodythat binds to the OD-1 receptor that inhibits T-cell proliferation and tumors were using this immune system of T-cells to their advantage. Basically, Keytruda inhibits immune response (which then therefore inhibits the antitumor response being hijacked by tumor cells).

purkinje cells structure and function

Lots of dendrites; all funneling to cell bodies; integration cells (lots of information goes to one place) Really smooth out muscle movements

What two compounds make up pigments of skin?

Melanin Carotene Skin blood flow also affects skin color

Pyramidal cells (found in the cerebral cortex) are ________-polar neurons

Multipolar

Fiber tracks that are white matter in the CNS (Cerebellum particularly) are: Designated by "M"

Myelin. That's what's making it white

What covers axon in PNS: ___1____ and ______2______ cells make this in the Peripheral nervous system (PNS)?

Myelin; Schwann

Do ependymal cells have a basal lamina?

No

glia limitans

Physical barrier between nervous tissue and pia mater composed of astrocytes The glia limitans, or the glial limiting membrane, is a thin barrier of astrocyte foot processes associated with the parenchymal basal lamina surrounding the brain and spinal cord.

Golgi tendon organs

Receptors sensitive to change in *tension* of the muscle and the rate of that change

Side polar contraction: Skeletal muscle, cardiac muscle or smooth muscle?

Smooth muscle

Where is this found? which muscle is this?

Smooth muscle in outer wall of "intestine" - O.L. is (out longitudinal; cross section cut), which is for pushing food down in peristalsis - I.S. is (inner circular) which is for vasoconstriction

Neuropil

The dense tangle of axonal and dendritic branches, and the synapses between them, that lies between neuronal cell bodies in the gray matter of the brain and spinal cord.

What is a diad in cardiac muscle?

The diad is a structure in the cardiac myocyte located at the sarcomere Z-line. It is composed of a single t-tubule paired with a terminal cisterna of the sarcoplasmic reticulum.

Full description of melanin formation:

The enzyme tyrosinase [converts tyrosine to 3,4-dihydroxyphenylalanine (DOPA)] is synthesized in the RER, processed in the Golgi, and accumulates in vesicles that also have a fine granular matrix of other proteins (stage I melanosomes). Melanin synthesis begins in ovoid stage II melanosomes where the matrix has been organized into parallel filaments onto which polymerized melanin is deposited and accumulates in stage III. A mature melanin granule (stage IV) has no tyrosinase activity and the internal matrix is completely filled with melanin. The mature granules (0.5 x 1 μm) are visible by light microscopy. Melanin granules are transported to the tips of the processes of melanocytes and then transferred to the neighboring keratinocytes of the basal and spinous layers. In keratinocytes, melanin granules are transported to a region near the nucleus, where they form a supranuclear cap helping to shield the DNA against harmful UV radiation.

glial limitans

The glia limitans, or the glial limiting membrane, is a thin barrier of astrocyte foot processes associated with the parenchymal basal lamina surrounding the brain and spinal cord.

What is Meissner's corpuscle?

They are a type of nerve endings in the skin that are responsible for sensitivity to light touch.

What is a pacinian corpuscle?

They are nerve endings in the skin or rectum, responsible for sensitivity to deep pressure touch and high frequency vibration.

Satellite cells vs astrocytes

They are thought to have a similar role to astrocytes in the central nervous system (CNS). They supply nutrients to the surrounding neurons and also have some structural function. Satellite cells also act as protective, cushioning cells.

When looking at a cross-section of spinal cord, is the posterior horn near the wider end or the thinner end (they are both pretty wide, the width is not dramatically different).

Thinner end (away from lumbar)

white matter of spinal cord

This area surrounds the gray matter. It is composed of both myelinated and unmyelinated axons. It has three regions, anterior, lateral, and posterior columns.

Check out the cork screw nuclei

This is a good indication that you're looking at smooth muscle

What is the arachnoid mater?

This is the web-like middle layer (Arachnoid trabeculae, like scaffolding)

What is a nerve impulse?

This term refers to the electrical signal conducted along a neuron, which can be transmitted to another neuron or an end organ such as a group of muscle fibers.

TnC, TnI, TnT

TnC: binds Ca+; TnI: binds actin; TnT: binds tropomyosin

What is Ca2+ role in cytosol

To float around and find troponin C to bind to

What is attached to minus end of actin?

Tropomodulin

Astrocytes provide the glial limitans, important role in Blood brain barrier, and involved in K concentration around neuron. True or false

True

At the junction between the molecular layer and the granular layer, THAT is where we find the Purkinje neurons or the cerebellum. True or false?

True

Ependymal cells have processes that branch and penetrate into adjacent neuropil to anchor them since they don't have a basal lamina to do so. True or false

True

The molecular organization of the sarcomeres produces staining differences that cause dark- and light-staining bands. True or false?

True

Type IIb skeletal muscle fibers

Type IIb Fast, white glycolytic fibers (large) Fewer mitochondria and less myoglobin than type I and IIa High concentration glycogen Depend largely on glycolysis for energy Adapted for rapid contractions and precise, fine movements e.g. Extraocular muscles, movement of digits "Fast twitch, fatigue-prone motor units"

How does melanin affect the color of the skin?

UV exposure darkens existing melanin and stimulates melanocytes. When melanocytes are stimulated, melanin is transferred from the melanocytes to keratinocytes in the stratum basale. - Melanin creates a UV protevting umbrella for kerotinocytes

What does calcium attach to troponin?

When the muscle cell is stimulated to contract by an action potential, calcium channels open in the sarcoplasmic membrane and release calcium into the sarcoplasm. --> Some of this calcium attaches to troponin, which causes it to change shape, exposing binding sites for myosin (active sites) on the actin filaments. --> Myosin's binding to actin causes cross-bridge formation, and contraction of the muscle begins.

Doral horn

Where are interneurons located in the spinal cord?

arborization

a fine branching structure at the end of a nerve fiber.

What is a myofibril composed of?

a long series of sarcomeres, separated by Z lines and containing thick and thin filaments that overlap in certain regions (between H zone and i band)

Cerebellar agenesis is

a rare condition in which a brain develops without the cerebellum. - The cerebellum controls smooth movement, and when it does not develop, the rest of the brain must compensate, which it cannot do completely.

Axoaxonomic synapse

a synapse with another axon - Can be excitatory or inhibitory

Type IV collagen is in

basement membrane (basal portion of Epithelial Cell)

Where is the subdural space?

between dura mater and arachnoid mater

Where are melanocytes found?

between epidermis and dermis Really between basal cells in the stratum basale (layer is one cell thick)

What's faster smaller or bigger diameter axon?

bigger

Cycling continues until _____________ ions are sequestered by the __________________

calcium; sarcoplasmic reticulum

Dendrites ramifiy (branch) because as they reach out they are increasing new connections by making

dendritic spines

What are both the epimysium and perimysium made of?

dense irregular connective tissue

What is the perimysium made of?

dense irregular connective tissue

If we have damage to a peripheral nerve, the damage ________ (directional term) to the cut will be removed by ___________. ANd then you have Growth cones that sprout out, and start to seek out where the nerve has previously had a synaptic connection. Schwann cells nearby start to make _________ Schwann cell covering around those growth cones. If you're lucky, hopefully, you can reconnect to where there was a synaptic connection with re-myelinated nerve. During this time you're going to have _________ of the muscle from a lack of electrical stimulation. With connection again and proper electrical stimulation, you will go back to the normal size and dimensions of the muscle.

distal; macrophages; nacent; atrophy

Bipolar neurons are commonly ________. A) motor neurons B) called neuroglial cells C) found in ganglia D) found in the retina of the eye

found in the retina of the eye

What is a sarcomere?

functional contractile unit of muscle

What is the shape of smooth muscle cells?

fusiform, torpedo shaped

Satellite cells in neuron

glia in the PNS and they allow for support of neuronal cell bodies ie. Dorsal root ganglion (which is distal to spinal cord) and we have a cell body that is pseudo-unipolar and we have satellite cells surround and supporting the cell body of the sensory neuron

anterior horn of spinal cord

grey matter; contains motor cell bodies affecting the axial muscles

Meniges

membranes that cover the brain and spinal cord

gray matter of spinal cord

nerve cell bodies arranged in a butterfly shape with anterior and posterior "horns"

Two types of cholinergic neurons

nicotinic Ach receptors and muscarinic Ach receptors

What kind of receptor for acetylcholine at the neuromuscular junction?

nicotinic acetylcholine receptor (nAChR), which is a ligand-gated ion channel.

Where do we find the nuclei of nuclei in skeletal muscle?

peripherally found just under sarcolemma

What do kinases do?

phosphorylate

Sarcolemma

plasma membrane of a muscle fiber

Release of inorganic phosphate from ADP on myosin head after ATP hydrolyzes will initiate the ______-______.

power-stroke

What is the basis of nerve gases that kill people?

prevent acetylcholine to be broken down by acetylcholine esterase

Fibroblasts

produce connective tissue (fibers and ground substance)

Each myofibril is a long series of ____________, separated by Z discs and containing thick and thin filaments that overlap in certain regions

sarcomeres

tactile cells (merkel cells)

sensory touch receptors

multipolar neuron structure

several dendrites and one axon

anterior horn

somatic motor neurons whose axons exit the cord via ventral roots

ventral horn

somatic motor neurons whose axons exit the cord via ventral roots

intercalated discs

specialized connections between myocardial cells containing gap junctions and desmosomes

Myelin improves a neuron's

speed

Five layers of thick skin

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Which layer is missing in thin skin?

stratum lucidum

Acetylcholinesterase

the enzyme that breaks down acetylcholine in the synaptic cleft; makes acetic acid and choline

dura mater

thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord

What is troponin-C attached to?

tropomyosin

melanin formation

tyrosinase oxidized tyrosine-> dihydroxyphenylalanine