Anatomical Terms, Histology, and the Integumentary System

anatomical position

body erect, palms up, feet flat

supine

lying face up, palms up

prone

lying face down, palms down

cephalic region

head

cervical region

neck

axillary region

armpits

brachial region

arms

thoracic region

chest

abdominal region

stomach

dorsal region

upper back

lumbar region

lower back

pelvic region

pelvis and hips

transverse or cross sectional plane

cuts body into superior and inferior halves

frontal/coronal sectional plane

cuts body into anterior and posterior halves

sagittal sectional plane

cuts body into left and right halves

anterior/ventral

front of the body

posterior or dorsal

back of the body

superior

higher up on the body

inferior

lower down on the body

cranial or cephalic

towards the head/skull

caudal

towards the tail

medial

facing the midline

lateral

facing away from the midline/outwards

proximal

closer to the torso

distal

away from the torso

superficial

on/closer to the surface of the skin

deep

inside the surface of the skin

histology

the study of cells and tissues

epithelial tissue

protective layer covering surfaces in contact with the outside world; skin and the gastrointestinal tract

functions: protection, absorption, and primary interface with the outside world

glands

organs of secretion; formed from epithelial tissue

apical

closer to the surface

basal

closer to body, deep

simple

single layer of cells

stratified

multiple layers of cells

squamous cell shape

flat in one dimension

cuboidal cell shape

cube-shaped

columnar cell shape

shaped like columns

simple squamous epithelium

one cell layer, delicate, slick and slippery surface reduces friction

location: in protected regions where absorption or diffusion takes place (kidneys, lining of the heart, blood and lymphatic vessels, air sacs of the lungs, body cavities)

stratified squamous epithelium

forms a series of layers, like plywood

location: located where mechanical stresses are severe (skin, anus, mouth, esophagus)

simple cuboidal epithelium

provides secretion, absorption, and limited protection

location: thyroid, kidney tubules, gland ducts, and ovaries

stratified cuboidal epithelium

cube-ish at the top, provides protection, secretion, and absorption; rare

location: lining of some ducts

transitional epithelium

permits repeated cycles of stretching without damage

location: bladder, renal pelvis, ureters

simple columnar epithelium

provides protection, secretion, and absorption

location: stomach lining, intestines, gallbladder, uterine tubes, and collecting ducts of kidneys

pseudostratified ciliated columnar epithelium

provides protection, secretion, and moves mucus with cilia

location: lining of nasal cavity, trachea, and bronchi, portions of male reproductive tract

stratified columnar epithelium

provides protection

location: small areas of pharynx, epiglottis, anus, mammary glands, and urethra

glandular epithelium

contains gland cells that are specialized for secretion

location: epithelia

villi

slender, finger-shaped projections of a mucous membrane

location: inner lining of the small intestine

cilia

organelles; slender extensions of the plasma membrane

location: on the free surface of an epithelial cell

endocrine glands

release products directly into interstitial fluid or bloodstream

location: pituitary gland, thyroid gland, hypothalamus, pineal gland, adrenal glands, ovaries/testes

exocrine glands

release products through ducts directly onto epithelial apical surfaces

location: sweat glands, mammary glands, salivary glands, sebaceous glands, lacrimal glands

connective tissue proper

a type of connective tissue made up of extracellular fibers and a carried cell population mixed in a viscous ground substance

ex: fibroblasts, adipocytes, and mesenchymal cells

loose connective tissue

fills spaces between organs, cushions/stabilizes cells, supports epithelia

areolar tissue

cushions organs, provides support and defense against pathogens

adipose tissue

provides padding, cushions shocks, provides insulation, and stores energy

reticular tissue

provides supporting framework

dense connective tissue

collagen dominant, fibrous

dense irregular connective tissue

interwoven meshwork, no consistent pattern

dense regular connective tissue

collagen fibers are parallel and packed tightly

elastic tissue

stabilizes spine and penis, cushions shocks, permits expansion and contraction of organs

tendon

attaches ligament to bone

ligament

connects bone to bone

aponeurosis

a sheet that attaches broad, flat muscle to another muscle or to several bones

formed elements of blood

blood cells and fragments of cells; erythrocytes, leukocytes, and platelets

lymph

fluid collected from the extracellular space and circulated in the body though the lymph system

plasma

watery matrix in blood, contains formed elements

erythrocytes

red blood cells; transports oxygen (and CO2) in the blood

leukocytes

white blood cells; nucleated cells which defend the body from infection and disease

platelets

membrane-enclosed packets of cytoplasm that function in blood clotting

supporting connective tissue

subcategory of connective tissue that includes bone and cartilage; important for the body’s framework, offers protection and leverage for skeletal muscles

cartilage

avascular substance, receives nourishment from the blood supply via diffusion

chondrocytes

cartilage cells; occupy small chambers known as lacunae

hyaline cartilage

provides stiff but somewhat flexible support, reduces friction between bony surfaces

elastic cartilage

provides support, tolerates distortion without damage and returns to original shape

fibrocartilage/fibrous cartilage

resists compression, prevents bone to bone contact, limits movement

bone

aka osseous tissue, is composed of calcium salts and collagen fibers, among other components; hard and flexible

osteocytes

bone cells, occupies lacunae in the matrix

osteoblasts

produce fibers and matrix of the bone

osteoclasts

dissolves fibers and matrix of the bone

canaliculi

passageways in the bone

periosteum

layer on the outside of the bone

compact bone

hard outside of the bone

spongy bone

porous inside of the bone

muscle tissue

responsible for the production of movement, contraction can be voluntary or involuntary; classified as skeletal, cardiac, or smooth muscle tissue

skeletal muscle tissue

attaches to the skeleton and each other and are primarily responsible for moving the body using the skeleton and other muscles for leverage; multinucleated, long and slender fibers; voluntary contractions

cardiac muscle tissue

responsible or the pumping function of the heart and circulation; short and branched, interconnected by intercalated disks; involuntary contraction

smooth muscle tissue

responsible for things such as contraction of the intestines, dilation and constriction of the pupils, and vasodilation and vasoconstriction of the blood vessels; short, spindle-shaped with a single, central nucleus; involuntary contractions

neural tissue

also called nervous or nerve tissue; essentially wires the entire body, allowing for communication of messages based on stimuli; 2 basic cell types: neurons and neural/glial cells

neuron

basic type of cell in nervous tissue

cell body

the body of a neuron, aka soma

nucleus

inside cell body, in the center

perikaryon

fluid on the inside of the cell body of a neuron

dendrites

branching processes that receive information

axon

conducts info from dendrites to other cells

myelin sheath

layer that covers axon

internode

large areas of axon wrapped in myelin sheath

nodes of ranvier

small gaps that separate adjacent internodes

axon hillock

thicker region of the cell body

telodendria/terminal branches

connects to synaptic knobs

synaptic terminals/knobs

ends of axon branches