SGU SVM HISTOLOGY: Cytology, Epithelium, CT Tissue+Cartilage+Bone, Muscles, Nerves+Brain

Periosteum vs. Endosteum

A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles. thin membrane that lines the medullary cavity of bones

Flagellum

A single long cilia, functions for movement Ex: Spermotazoa

Oligodendrocytes (CNS)

A type of glial cell that forms insulating myelin sheaths around the axons of neurons in the CNS

Nervous System

Composed of neurons and neuroglia Neurons--Structural and functional units Neuroglia--supporting cells for nerves

Mesenchymal tissue

Composed of stems cells and amorphous fluid filled ground substance, gives rise to various types of adult tissues EMBRYONIC CT

Dense CT

Composed of thick collagenous fibers, few fibroblast cells Dense regular-- in capsules of organs, deep layer of dermis Dense irregular--tendons, ligaments and aponeurosis ADULT CT

What are myofibrils made up of?

Composed of thick filaments made of myosin and thin filaments composed of actin, troponin, and tropomyosin sarcomeres

Osteons

Contains Haversian/ central canals, and Volkamans/transverse canals surrounds by concentric lamellae. Lacuna contain osteocytes b/w lamellae Central canal contains blood vessels, nerves and loose CT.

Sooth Endoplasmic Reticulum FUNC

Functions to detoxify lipid metabolism and drug, also helps in the recapture of calcium in muscle cells

Enchondral-- Secondary Ossification Stages

IN LONG BONES Both epiphyses, same process as primary but at puberty the plate becomes ossified as growth stops Projections of bones (trochlear, condyles, etc), other secondary centers are formed.

Development of Glands

If development stays attached it is exocrine Detached it becomes endocrine and filled with capillaries

White vs. Grey Matter in Brain

In cerebrum, cerebellum grey matter is peripheral, white matter is central *In brain stem, aggregates of neural cell bodies form patches of grey matter embedded in white matter. CALLED NUCLEI*

Satellite cells

Inactive myoblast Activate to heal skeletal muscle

Duct System

Intralobular==> Within lobule *smallest* Interlobular==> In b/w lobes Lobar Ducts==> Duct of lobe Main =Ducts==> Duct of a gland

Smooth muscle

Involuntary non-striated narrow, tapered rod-shaped Walls of internal organs: ie. stomach, intestines, and blood vessels. UNINUCLEATED

Unipolar neuron

It is a single extension that branches out in two directions. It has a receptive pole and an output zone. found in sensory nerves

Glycogen

It is a stored formed of glucose/energy manufactured by the liver can be seen with PAS reaction

How are mitochondria stained?

Janus Green B stain for living cells

Differences between Cardiac and Skeletal

Less striations Nucleus centrally located as striations are not squishing them Capillaries are much bigger Fibers branch and anastomose throughout (blue brackets)

Osteocytes

Lie in a lacuna, derived from osteoblasts embedded in the bony matrix (surrounded by calcified interstitial matrix)

Elastic fibers

Long and thin fibers that form branching networks in the matrix. They contain a protein called elastin which allows the fibers to stretch and recoil like rubber bands. These fibers are found where the tissue is constantly expanding like the skin, lungs, and blood vessels. Stained with orcein and resorcin-fuchsin

Stereocilia

Long, rigid, microvilli, found in the inner ear

Lysosomes and function

Lysosomes are vesicles containing hydrolytic enzymes that digests things like food and viral/bacterial particles. Things you want to digest gets into a vacuole by endocytosis or phagocytosis, and then the vacuole fuses with the lysosome. Anything inside gets digested by the hydrolytic enzymes. Is primary lysosome as soon as it is excreted, doesn't become secondary lysosome until it fuses with phagosome/autophagic vacuole

Multinucleated vs. Multilobulated

MN--Skeletal muscle cells and osteoclasts ML--Barr body **Normally only contains one nucleus in a cell, normally no lobes

Collagen fibers

Made of collagen, provides support, extremely tough, high tensile strength, no stretch. Have a wavy arrangement. are able to be stained red with Van Giesons' method or blue with mallory's and masson's trichrome stain

Where is stratified columnar found?

Mainly in larger ducts such as parotid (intestinal) and mandibular (salivary) gland ducts

Fibrocartilage

Matrix similar to but less firm than that of hyaline cartilage;thick collage fibers predominate. found in intervertabral discs and menisci

What are encapsulated receptors?

Meissner's corpuscles (tactile corpuscles) Pacinian Corpuscles (lamellated corpuscles) Muscle spindles, Golgi tendon organs, and Ruffini's corpuscles. Joint Kinesthetic Receptors. Krause's genital corpuscles Neurotendinous and neuromuscular spindles

What is cartilage?

a type of flexible connective tisssue, has chondroblasts, chondrocytes and matrix.

What is an axo-axonic synapse?

axon innervates a neighboring axon instead of the dendrite or cell body

What is an axo-somatic synapse?

axon innervates a nerve cell body directly using electron dense plaques

What is an axo-dendritic synapse?

axon innervates dendrite, most often seen

What is white matter in the spinal cord?

axons (processes) dorsal, ventral, and lateral funiculi

What is a compound gland?

branching gland with multiple larger collecting ducts Compound tubular Compound alveolar or acinar Ex: Parotid Compound tubule-alveolar Ex: pancreas

What are the two main minerals stored in the bone matrix?

calcium and phosphorous

What is spongy bone?

cancellous bone

List structural units from smallest to largest

cell--tissue--organ--system--body

Mast cells

cellular bags of granules located in the loose connective tissues close to blood vessels Secrete heparin and histamine, blood thinner and swelling agent to prevent further spread of toxin in body

Compact bone

dense outer layer of bone composed of osteons, outer, inner, and interstitial lamellae.

Heterochromatin

densely packed, basophilic clumps that shows up in inactive cells (stains dark)

Peroxisomes

detoxifies in liver and kidney Ex: alcohol

Adipocytes

fat cells Unilocular--Lg liquid droplets, nucleus dispersed to periphery Multiocular--Brown fat, central nucleus, multiple lipid droplets, lots of mitochondria in cytoplasm. Found in young and hibernating animals

Lipids

fat in adipose tissue can be seen with osmic acid fixation

Myofibroblasts

fibroblasts that contain actin filament, play a role in contraction during wound healing

Golgi apparatus complex

flattened stacks that process, package, and deliver proteins and lipids from the ER

What is loose or areolar tissue?

found beneath the epithelium (lamina propria, hypodermis) and around blood vessels and nerves, in serous membranes ADULT CT

Mucous or gelatinous CT

found in the umbilical cord in the embryo, in the papillae of the omasal lamina, in the reticular fold, and in the glans penis of the bull. Has stellate fibroblasts, and gel like ground substance with collagen fibers EMBRYONIC CT

What are nonecapsulated receptors?

free nerve endings, tactile corpuscles

What are the two types of of impulse receptors on a dendrite?

gemmules and electron dense plates

What is the only unicellular gland in the mammal?

goblet cells, in the intestine, secretes mucus to move food along

Mitochondria

has its own DNA, and some ribosomes creates ATP for the cell to use *Powerhouse of the cell*

Cardiac Muscle

heart muscle, striated, involuntary MULTINUCLEATED

Nucleus

highly basophilic structure in the cell that contains the nucleolus/nucleoli, chromatin (DNA), and a nuclear matrix.

What are the five major types of ground substances?

hyaluronis acid--body of eye and synovial fluid chondritin sulfate--cartilage, bone, lg. blood vessels dermatin sulfate--tendons, ligaments keratin sulfate--cartilage, bones heparin sulfate--arteries, lungs

Mesenchymal cells

irregularly shaped with multiple processes. Stem cells, all other cells arise from these

Hemosiderin

result of hemoglobin degradation

Microglial cells (CNS)

macrophages of the CNS

Elastic tissue

made of numerous regularly or irregularly arranged elastic fibers, Ex: Nuchal ligament and vocal cord ADULT CT

Reticular tissue

made of reticular cells and a network of reticular fibers, Ex: spleen, lymph node and liver ADULT CT

Where is a mixed serous and mucous gland found?

mandibular salivary gland

What is a cytocrine gland?

material of one cell is able to diffuse into surrounding cells (melanocyte)

Chondrocyte

mature cartilage cell, located in lacuna

What is the apocrine gland?

membrane bound granule of cytoplasm and secretion that separates away from the cell. sweat or mammary excretion

What makes up cilia?

microtubules Ex: Respiratory tract

What is the cell body of a nerve called?

perikaryon Nucleus is centrally placed, ovoid or spherical, cytoplasm has Nissl bodies, neurofilaments, microtubules, prominent Golgi apparatus (secretes neurotransmitter and neurohormones), numerous mitochondria and lipofuscin pigments

What is the motor end plate?

pocket formed around motor neuron by sarcolemma, about 40-50 nm gap between

What makes up the amorphous ground substance?

proteoglycans, glycosaminoglycans and interstital fluid

Functions of the Golgi complex

provides site for accumulation, concentration and packaging of secretory proteins into membrane bound vesicles Also is for the biosynthesis of glycoproteins, glycolipids, phospholipids and neutral lipids

Where is transitional epithelium found?

urinary bladder, urethra Always has at least 5 or 6 layers so it can expand, can do so out to 50 times its length

Cytoplasmic Inclusions

*Stored material (not live)* Glycogen Lipids Melanin Hemosiderin Lipofuscin

Euchromatin vs. Heterochromatin vs. Nucleolus

(EC) Lightly stained, relatively active (HC) Darkly stained, relatively less active (NU) Darkly stained w/ granules

Osteoclasts

*Multinulcleated* ruffled border, functions to break down bones (with acid and lysosomal enzymes) to sculpt them to the right shape. Mostly occurs in development and bone repair.

Intermediate filaments

*Provide mechanical stability among cells* keratin desmin lamins glial fibrillary acid proteins (GFAP) neurofilaments

Sensory ganglia

Collections of unipolar cell bodies outside the central nervous system Associated with the spinal and cranial ganglia

What are the functions of the cell membrane?

1. Selectively permeable 2. Reception sites for antigen recognition and immunological mechanisms (phagocytosis) 3. Receptor sites for hormone activated events

How big are ribosomes?

15-25 nm in diameter

How wide is the perinuclear space in a nuclear envelope?

2 concentric membranes with perinuclear space 25 nm wide. It is almost 2.5 times wider than the cell membrane which is why is shows up so clearly when stained

What is the cell membrane composed of?

2 leaflets of phospholipid molecules Polar--Hydrophilic heads face both cytoplasm and extracellular space Non-polar--Hydrophobic tails pops each other

How thick is the average cell membrane?

8 to 10 nm in width

Osteoblast

Columnar or squamous On surface of bone, secretes osteoid, help in the formation of new bone by making proteins and linking collagen

NERVE REPAIR

A. Normal nerve fiber with muscle B. Injured=>nissl bodies move to site=> nerve fibers distal to injury degenerate=>muscle fibers show atrophy C. Regeneration=> Schwann cells or oligodendrocytes proliferate=>axon grows=>Muscle fiber atrophied=>Debris is phagocytosed by macrophages or microglial cells D. Muscle fiber regenerated=>Nissl bodies return to neuronal cell body

Neurolemmocytes (PNS)

AKA Schwann cells that produce myelin in the PNS

What are myoepithelial cells?

Act as tiny muscles to push out mucous

Peripheral Nerves from Spinal Cord

Afferent (sensory nerves) form dorsal root Efferent (motor) form ventral root Spinal nerve is formed by union of these

Glycocalyx

An extracellular coating that provides protection to the cell from mechanical and chemical damage

Amorphous Ground Substance

Composed of glycosaminoglycans (GAGs) and protoglycans Cells and fibers of CT are embedded here

Ribosomes

Are acidic (basophilic), *only substance outside of nucleus that is basophilic* protein synthesis, outer membrane of nuclear envelope is studded with these (rough ER)

What are the levels of the basement membrane?

BASAL LAMINA Top layer---Lamina Lucida (low density fibers/ collagen) Middle layer--Lamina densa (thicker proteoglycans and collagen Bottom layer-- RETICULAR LAMINA (reticular fibers), connects the lamina densa to the subepithethial connective tissue

Intramembranous Ossification Stages

Bone laid down in aggregates of mesenchymal cells--differentiate to osteoblasts--turn to osteocytes in matrix--osteoclasts come in to clean up, shape

Muscle Cell Regeneration

CARDIAC--No regeneration after birth, damage is replaced by connective tissue SKELETAL--Limited regeneration, satellite cells SMOOTH--Active regeneration, mitosis of smooth muscle cells

Cerebrospinal fluid

CSF, produced by choroid plexuses in ventricles, physical protection for brain and spinal cord

Meninges

Called Dura mater or pachymenix Contains=> Epidural space for dorsal root nerve block (childbirth) Subarachnoid space (CSF collection)

Central Canal

Cavity of the spinal cord. Lined by ependymal cells *simple columnar cells*, full of cerebrospinal fluid

Structure of smooth muscle

Cells are elongated, spindle shaped with a single central nucleus Many thin filaments, thick are sparse, thin filaments only have actin and tropomyosin

Pigment cells

Cells containing pigments (melanin)

What is a merocrine gland?

Cells secrete via exocytosis

Ganglia

Clusters of cell bodies in the PNS, only two types, sensory and autonomic

Bipolar neuron

a neuron with only one axon and one dendrite, found in the retina

Stratified squamous epithelium (non-keratinized)

Cornea, vagina

Reticular fibers

Delicate, flexible, elastic fibers NETWORKS around capillaries muscle fibers and nerves. FRAMEWORK of liver, endocrine, lymphatic organs. Can be stained with silver impregnation or PAS

Dense bodies

Dense bodies are attachment sites within the sarcoplasm (cytoplasmic dense bodies vs. sarcolemmal dense bodies) of the smooth muscle cells for the myofilaments (actin and intermediate, NO myosin).

Where is stratified cuboidal epithelium found?

Ducts of salivary glands or occasionally in sweat glands Generally 2 layers, rare to have 3. Functions as protection for other layers

Hormonal activated cellular events on cell membrane

Endocrine gland=thyroid, pituitary, adrenal, an abundance of *Rough Endoplasmic Reticulum* Exocrine=released directly into the blood with no duct, an abundance of *Smooth Endoplasmic Reticulum*

Larger Muscle Layers

Endomysium (basal lamina, and reticular fibers) Perimysium (dense irregular CT) Epimysium (dense irregular CT)

What is a holocrine gland?

Entire cell is released with the secretory product (sebaceous gland)

Where is keratinized stratified squamous epithelium found?

Esophagus, mouth, epidermis of the skin, and dry membranes. Only kind of cell that is keratinized

Satellite cells

Ganglionic gliocytes, they wrap the unipolar neuron cell bodies in the sensory ganglia, and loosely wrap multipolar nerve cell bodies in autonomic ganglia

What makes up the intercalated disc in cardaic muscle?

Gap junctions

What are exocrine glands?

Glands that produce a secretion and release it outside the body (sweat and oil glands)- has system of ducts

What the zonula adherens?

Held together by TP and a bundle of actin filaments. This is stronger than tight junction Ex: Lining of the intestine (basal)

What are gap junctions?

Held together with TP Interlocking like a zipper AKA Communicating junction Ex: Only in cardiac muscle

What are macula adherens?

Held together with TP, actin filaments, and electron dense plate AKA Desmosomes Ex: Epidermis

Hematoxylin and Eosin (H&E)

Hematoxylin (Basic dye)--stains nucleus (which is acidic or basophilic) purple/dark blue Eosin (Acidic dye)--stains cytoplasm (which is basic or acidophilic) pink/red

What are hemidesmosomes?

Hemi=half Resemble desmosomes but they do not link adjacent cells. On the outside of the plasma membrane they attach to the protein laminin. Present in the basement membrane.

Endochondral-- Primary Ossification Stages

Hyaline Cartilage Base Starts in diaphysis--then periosteal collar develops around shaft (osseous tissue formed by chondroblasts differentiating into osteoblasts) Cartilage degenerates, replaced by mesenchymal cells differentiating into osteoblasts--creates osseous tissue

What are purkinje fibers?

Modified myocardio fibers that have less contractile elements, rapidly conduct impulses, last resort when other pacemakers fail. speciecalized impulse conducting fibers

Fibroblasts

Most common cells, responsible for the synthesis of of fibers and ground substance (for wound repair). Fibrocytes are when fibroblasts are less active, producing less.

Autonomic ganglia

Motor (sympathetic, parasympathetic and enteric) Throughout the visceral cavities, are multi polar

Order of Skeletal Muscle Fiber Cells

Myofilaments--Actin and Myosin Myofibrils--Bundles of myofilaments Myofiber--Entire cell

Nuclei shapes

Normal--Spherical or ovoid Smooth muscle--spindle shaped Monocytes--bean or kidney shaped Neutrophil leukocytes--multilobulated

What are the nuclei in the brain?

Nuclei are a collection of neuronal cell bodies within the CNS. Some of these nuclei control vital body functions, e.g. cardiovascular centre in medulla oblongata

Organelles vs. Inclusions

Organelles are the functional parts of the cell Inclusions are the structural parts of the cell

BONE REPAIR

Osteoblasts of periosteum and endosperm proliferate Nearest bone fragment form bony trabeculae Those farther away differentiate into chondroblast to produce cartilage Later cartilage is replaced by bone like endochondral ossification Osteoclasts invade for bone remodeling

Cerebellum

Outer, inner layers are folded=>folia 3 layers of cerebellar cortex Outer molecule layer=>neutrophil arranged horizontally Inner Granular Layer=>Densely packed small neurons with intensely stained nuclei *INTERMEDIATE PURKINJE LAYER*=> Single layer of piriform cells, send ramified (branched) dendrites into molecular layer, axons into white matter.

What makes the cell membrane trilaminar?

Phospholipid, protein, and glycocalyx coat outer and inner layer (electron-dense) separated by a electron-lucent intermediate lamina

Microtubules

Provide structure for cell, function in maintenance of cell form, transport of organelles and vesicles. Play an essential role in cell division and are a major component of centriole

What is the function of the cytoskeleton?

Provides support, gives shape, (columnar, round, flat etc.)

Nissl bodies

Rough ER in a nerve cell

What is a simple gland?

Simple tubular==> longer, hard to find Simple acinar==> more like a sack Simple Branched tubular/acinar==> more common

Telodendron vs. Telodendria

Singular--One terminal branch of axon Plural--Fine extensions of distal axon Each one ends in an expansion called terminal bulb where neurotransmitters molecules are packaged and stored within a synaptic vesicle

Synapse/Synaptic Cleft

Sites where contact occurs b/w two neurons or or b/w neurons and other effector cells, cleft is the space

Cerebral Cortex

Six layers from superficial to deep Pyramid Shapes are only found in the cerebral cortex

Red muscle fibers

Skeletal muscle fibers that have a high myoglobin content and appear darker. They also contain more mitochondria and are supplied by more blood capillaries. (slow twitch==>endurance)

White muscle fibers

Skeletal muscle fibers that have a low myoglobin content and appear lighter. (fast twitch==>sprinting)

Microvilli

Small projections that increase surfaces area for absorption Ex: Kidneys and small intestine

Nucleolus

Spherical, basophilic, composed of loops of DNA which contain a group of rRNA genes **Involved in the synthesis of rRNA and its packaging into the precursor of ribosomes *Produces DNA and rRNA*

Hyaline cartilage

Stiff, flexible support Reduces friction between bones (articular surfaces) Found in synovial joints, rib tips, sternum, and trachea

Shape of nucleus...

Tends to determines the shape of the cell Ex: Flat nucleus=flat cell, Rounded nucleus=oval, cuboidal, or hexagonal

What are syncitium?

The complex of intercalatediscs in cardiac muscle connecting myofibrils

Multipolar neuron

a neuron that has many processes coming off of the cell body; motor neurons are multipolar. found in the CNS

Endoneurium vs. Perineurium vs. Epineurium

These are delicate connective tissue that surrounds each nerve fiber, Schwaan cell and thin C.T. Goups of nerve fibers that are bound into fascicles by these coarse connective tissue wrappings surrounds the entire nerve bundles

Ependymal cells (CNS)

These are glial cells that line the central cavities of the brain and the spinal cord. These have cilia that helps to circulate cerebrospinal fluid that filled cavities and protects the CNS

Macrophages

They are big eaters that engulf debris, foreign materials, bacteria, and viruses. have lots of lysosomes Eat all blue dye--

Proteoglycans

They are glycoproteins that are heavily glycosylated to a protein core

Astrocytes (CNS)

They are the MOST NUMEROUS GLIAL CELL, they fill spaces between neurons for support, and make up the blood brain barrier

Sarcomere

Thick filaments show up as the darker lines

What is a mucous gland?

Thick, slimy secretion (contains mucin protein), stains lightly

What are tight junctions?

Tightest, creates a nearly water tight barrier between cells. Barrier to lateral movement of membrane proteins. Ex: intestines (Belt network)

What are the proteins in the cell membrane?

Transmembrane--Goes between hydrophilic and hydrophobic layers connects them together Peripheral membrane--contain receptors, located on outside of cell

Dendrites vs. Gemmules

Trasmit the impulse toward the cell body. Dendritic spines

Cell Junctions

Use transmembrane proteins to connect

What is a serous gland?

Watery secretion (ex. sweat)

Astrocytes in White Matter vs. Grey Matter

White--Processes are long and slender, moderately branched called fibrous Grey--Processes are shorter and highly branched, called protoplasmic BOTH FUNCTION THE SAME

Microfilaments

actin and myosin assist in membrane activities such as endocytosis, exocytosis, and cell migratory activity

Where is simple squamous epithelium found?

air sacs in the lungs, pleural and peritoneal cavities, glomerular capsules, blood vessels linings

Plasma cells

antibody producing cells HAVE CART-WHEEL LIKE APPEARANCE OF NUCLEUS Abundant in lymphatic nucleus

Rough Endoplasmic Reticulum FUNC

assists with protein synthesis because it is covered in ribosomes

Cartilage matrix

composed of fibers and ground substance containing proteoglycans and GAGs. Shows marked metachromasia (certain stains change color in presence of certain biological materials)

What is the overall function of connective tissue?

connects other tissue and provides a framework to support the entire body by cartilage and bones

Where is simple columnar epithelium found?

digestive tract

What are endocrine glands?

ductless glands that produce hormones

What cell in mature mammals lacks nucleus?

erythrocytes

What cell lacks ribosomes?

erythrocytes

Barr body

inactive X chromosome (type of white blood cell), can be seen in neutrophils of females *Multilobulated*

Lipofuscin

indigestible residue of phagocytosis, commonly found in cardiac muscle and nerves, used to age an animal

Where is simple cuboidal epithelium found?

kidney tubules, thyroid gland

Euchromatin

less condensed, abundant in active cells, and uniformly dispersed (stains lightly) More EC than HC means the cell is relatively active

What is gray matter in the spinal cord?

nerve cell bodies Ventral Grey Matter (horn)=> efferent neurons Dorsal Grey Matter=>Interneurons Lateral Grey Matter=>Autonomic neurons

Chondroblast

oval-shaped cell that secretes the cartilagenous matrix, found in growing animals spherical nucleus, basophilic cytoplasm

How is the Golgi stained?

silver salt or osmium-makes it appear as a black network of cisternae

Elastic cartilage

similar to hyaline cartilage, but more elastic fibers in matrix, pinna and epiglottis

Melanin

skin and eye pigment

What are lacunae?

small cavities that contain osteocytes and chondrocytes

ANS vs. CNS vs. PNS

smooth muscle, cardiac muscle, glands Brain and spinal cord Cranial and spinal nerves

Pericytes

specialized cells of connective tissue- surround endothelial cells of capillaries, small venules- important in production of ground matrix. Can change to myofibroblasts to facilitate healing of cut capillary

Cell shapes

squamous, cuboidal, columnar

Reticular cells

stellate shaped cells that produce reticular fibers. Spherical nucleus and basophilic cytoplasm

Skeletal muscle

striated and voluntary MULTINUCLEATED

Stroma

supportive framework of the parenchyma in a gland

What organs have collagen fibers?

tendons, ligaments and organ capsules

Intramembranous Ossification vs. Endochondral Ossification

the formation of bone from fibrous membranes, mesenchymal cells Ex: skull bones (except base) AKA Intracartilagenous the formation of bone from pre-existing hyaline cartilage models. Stretches, changes and grows with growing organism Ex: appendicular skeleton, vertebral column, base of skull

Parenchyma

the functional tissue of an organ as distinguished from the connective and supporting tissue. can be serous or mucous

Chromatin

the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.

What is osteoid?

the organic part of the matrix of bone, eventually calcified by deposition of calcium salts

How are mast cells stained?

toluidine blue metachromatic granules change color of stain, blue becomes red

Where is pseudostratified columnar epithelium found?

trachea and bronchi (ciliated form) Composed of a single layer, but because of the diff. cell shapes and nuclei at diff. levels, looks stratified.

Axon hillock

where the cell body transitions to the axon, and where action potentials are initiated

Leukocytes

white blood cells, lymphocytes, monocytes, and granulocytes (blood cells).