Glossary of Terms

adipocytes

mature cells found in adipose (fat) tissue - filled with a large storage sac of lipid. The lipid in these cells does not stain well with H&E staining, so the cells appear empty.

agranulocytes

without prominent-staining cytoplasmic granules

anucleate

without a nucleus

apical

the exposed side of epithelial tissue

aponeuroses

connective tissue connections between to muscle groups

articular cartilage

cartilage that surrounds the articular surface of bones (surfaces where bone meets bone to form a joint). This cartilage decreases friction in movement and provides cushioning

articulate

two bones connecting to form a joint

Avascular

without blood vessels

Axon

axon hillock of the cell body narrows to become the axon, which transmits electrical signals to the axon terminus to communicate with other cells

basal

the anchored side of epithelial tissue

basement membrane

a thin layer of connective tissue that anchors the cells of epithelial tissues to the deeper structures of our body

biconcave

narrow in the center and thicker on the edges, RBC's are biconcave or shaped like a donut (if the icing touched in the center)

bone matrix

extracellular matrix containing collagen, calcium-binding proteins, calcium and phosphate depositions

branched

branched cells will resemble the letter Y. A branched cell may connect to one cell on one end, but two cells on the other end.

canaliculi

meaning "tiny canal"

Cell body

contains nucleus and organelles and serves as the biosynthetic center of the cell (synthesizes biological molecules)

central canal

running the length of the osteon, containing blood vessels and nerves

chondrocytes

mature cells found in cartilage that monitor and maintain the cartilage extracellular matrix

chromatin

DNA wrapped around histone proteins

chromosomes

tightly coiled, condensed DNA wrapped around proteins

cilia

surface appendages found in some epithelial cells that move in a rhythmic manner to move mucous across the apical suface of the tissue

cleavage furrows

pinching or narrowing of the plasma membrane during cytokinesis

Collagen

Collagen is a fibrous protein that has many structural types

Columnar

a tall, rectangular cell with an egg-shaped nucleus

concurrent

occurring with or simultaneous

cross section

a transverse section, cutting perpendicular to the length of a structure. If cutting a tubular structure, a cross section would produce a ring of tissue

Cuboidal

a cube-shaped cell with a round nucleus

cutaneous plexus

a network of blood vessels in the skin

Cytokinesis

occurring with mitosis, cytokinesis is the division of the cytoplasm resulting in two new cells

deep

closer to the center, away from the surface

Dendrites

receive stimuli (signals/information) from environment or other neurons, which are conducted to the axon

dermis

the deepest region of the skin (underlying the epidermis), consisting of two layers: the papillary layer is areolar connective tissue and the reticular layer is dense irregular connective tissue

desmosomes

cell junction that allows tissues to resist pulling and tearing

diaphysis

a long central shaft of a long bone, containing the medullary cavity surrounded by compact bone

eccrine sweat glands

secrete watery sweat that assists in thermoregulation (homeostasis of body temperature) and additionally secrete some waste products and provide some protection against microorganisms

Elastic fibers

provide elasticity to tissues - the ability to be pulled and recoil like a rubber band

Embryonic origin

The embryo has three major layers - endoderm, mesoderm, ectoderm.

endosteum

connective tissue membrane lining the internal surfaces of bone

endothelium

the specialized simple squamous epithelium that lines the lumen of blood vessels

epidermis

superficial region of the skin, -epi means above or upon (above/upon the dermis)

epiglottis

located in the larynx (throat), moves to prevent food from entering the trachea (airway) during swallowing

epiphysis

the end of a long bone, containing a core of spongy bone surrounded by an outer covering of compact bone

erythrocytes

red blood cells, biconcave cells lacking a nucleus and organelles that contain ~250 million molecules of hemoglobin

extracellular matrix

structural proteins and surrounding ground substance

extracellular matrix (ECM)

the fluid, macromolecules, and minerals that surround cells in our tissues, specifically connective tissues

fibroblasts

cell type found in connective tissue that actively produces the proteins in the extracellular matrix

gap junctions

cell junction that allows passage of ions from the cytoplasm of one cell to the cytoplasm of the neighboring cell. The flow of ions allows cardiac muscle tissue to communicate electrically.

Glial cells

cells that play an important role in supporting neurons and the nervous system

goblet cells

uni-cellular mucous-producing gland found in epithelium

granulocytes

contain prominent-staining cytoplasmic granules

ground substance

consists of soluble proteins, nutrients, ions, waste products, dissolved gasses

H&E

hematoxylin and eosin staining protocol

Hematoxylin - purple/blue, stains nucleic acids (basophilic) - highlights nucleus and rough ER (ribosomes have RNA)
Eosin - pink, stains proteins (acidophilic) - highlights connective tissue proteins (collagen), plasma membrane, cytoplasm

hair follicle receptor

nerve endings that wrap around the base of the hair follicle for sensation of touch

homeostasis

a dynamic (constantly adjusting) state of equilibrium

hypodermis

layer of connective tissue, primarily adipose tissue, located deep to the dermis

innervated

having nerve endings for sensory or motor function

intercalated discs

specialized cell-to-cell connections in cardiac muscle tissue containing gap junctions and desmosomes

interphase

During Interphase the cell carries out normal functions, grows, and replicates its DNA

interstitial fluid

the fluid in between our cells

involuntary

under sub-concious control, occurs without you thinking about it.

keratinized

containing keratin, a structural protein found in skin, hair, and nails

lacunae

A gap, cavity, or depression. Osteocytes (bone) and chondrocytes (cartilage) are found within lacunae.

lamellae

sheets or layers

leukocytes

white blood cells, function in immune response

longitudinal section

cut along the long axis of a tissue

lumen

the interior of a tube-shaped organ, like a blood vessel, kidney tubule, or intestines

lymphocytes

a type of lymphocyte (white blood cell) that is part of our adaptive immune system (i.e., B-cells and T-cells)

macrophages

phagocytic cells that engulf (phagocytose) cellular debris or pathogens

melanocytes

pigment (melanin)-producing cells in the epidermis

mesenchyme

loosely arranged connective tissue in the embryo that originates from the mesoderm

Mitosis

nuclear division that separates the replicated chromosomes resulting in two nuclei

multinucleated

cell that contains many nuclei

Neurons

excitable cells that can receive and send electrical signals

Nissl bodies

granular substance in neuron cell body caused by the staining pattern of the rough ER

nucleated

containing a nucleus

osteoblasts

immature bone cells that deposit new bone matrix

osteocytes

mature cells in bone tissue that monitor and maintain the osseous tissue matrix

osteogenic cells

stem cells in bone that can form osteoblasts and osteocytes

osteons

the functional unit in compact bone, consisting of a central (Haversian) canal surrounded by concentric rings/layers of bone matrix called lamellae

papillary layer

superficial layer of the dermis, made of areolar connective tissue

periosteum

connective tissue membrane lining the external surfaces (non-articular) of bone

peripherally-located

located to the outside (peripheral)

perpendicular canals

running at right angles to the central canal, containing blood vessels and nerves

plasma

the fluid in blood, containing dissolved solutes such as: proteins, blood gasses (CO2 and O2), hormones, nutrients, waste products

platelets

fragments of a cell precursor (megakaryocytes) that function to stop bleeding of a damaged blood vessel

Polarity

having two sides with different structural or functional characteristics.

regeneration

the ability of a tissue to repair itself or to replace old cells with new cells

regeneration capacity

the ability of a tissue to repair or replenish itself

reticular fibers

a specialized type of collagen that forms branching networks (branches on a tree) instead of long, linear strands

reticular layer

deep layer of the dermis, made of dense irregular connective tissue

reticulocytes

mature cells found in reticular connective tissue, responsible for making reticular fibers

scaffold

a structural support system

sebaceous glands

secretes sebum (oil) that helps lubricate the skin and protect against microorganisms

Simple

in epithelial tissues, a single layer of cells anchored to a basement membrane

soma

means "body"

Squamous

a scale-like, flattened cell with a disc-shaped nucleus

Stratified

in epithelial tissues, a layer of two or more cells with the basal layer anchored to a basement membrane

striated

perpendicular "striped" appearance of skeletal and cardiac muscle cells

superficial

closer to the surface

thermoregulation

regulation of body temperature

trabeculae

plates/spikes of bone matrix found in spongy bone

uninucleated

containing a single (1) nucleus

vascularized

containing blood vessels

voluntary

under concious control - you can actively choose to move your skeletal muscles

white fish blastula

a blastula is a sphere of cells produced during the development of a white fish embryo by repeated mitosis and cleavage of a fertilized egg

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Anatomy and Physiology I: An Interactive Histology Atlas Copyright © 2024 by Karen Wiles; Christina Wilson; Juan Manuel Ramiro-Diaz; Georgios Kallifatidis; and Soma Mukhopadhyay is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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