a&p exam 2

tissues

Cells are organized into __

tight junction

__ allows membranes to cover and fuse

desmosomes

__ bind cells by forming “spot welds” between cell membranes

gap junctions

__ link the cytoplasm of adjacent cells and allow ions and nutrients to move

Epithelial Tissues

cover organs and body surfaces, line cavities and hollow organs, and make up the glands

free surface (apical) ; underside (basal)

epithelial tissues have __ on the outside and __ anchored by connective tissue by a thin, non-living layer called the basement membrane

simple squamous epithelium tissue

fits tightly together like floor tiles, nuclei are broad and thin, and make up the walls of air sacs (alveoli), capillaries and lines blood and lymphatic

(FOUND IN DIFFUSION AND FILTRATION SITES) 

Simple Cuboidal Epithelium Tissue

A single layer of cube-shaped cells with centrally located nuclei and lines kidney tubules, thyroid follicles, ducts of some glands

(SECRETION AND ABSORPTION)

Simple Columnar Epithelial Tissue

is when the nuclei are usually at the same level, near the basement membrane (taller)

^^ secretion and absorption & protection ^^

goblet cells

__ secrete a protective fluid called mucus on the free surface of the tissue and is known as a simple columnar tissue

microvilli

__ increased surface area of the cell membrane → cells that are specialized for absorption and is known as a simple columnar tissue

pseudostratified columnar epithelium tissue

when nuclei are at 2 or more levels and cells vary in shape, but all reach the basement membrane (often have cilia, goblet cells)

^^ protection from infections ^^ Lines respiratory passageways → mucus covered linings are sticky and trap dust → microorganisms and cillia wipe them away

lumen

Within simple cuboidal epithelium tissues, free layer faces the hollow channel or __

stratified squamous epithelial tissue

when tissues have many cell layers; thick —> protective; lines the oral cavity, vagina, and anal canal, and esophagus

keratinized

Within stratified squamous epithelial tissues, the epidermis is __ 

dry, tough, protective

keratinized allows for a __ material

stratified cuboidal epithelial tissue

have 2-3 layers of cube-shaped cells to form the lining of the lumen (more protection than 1 layer), line the ducts of mammary, sweat, and salivary glands, and the pancreas

stratified columnar epithelial tissue

has several layers of cells, the top layer of elongated cells, cube-shaped cells in deeper layers, and lines part of the urethra (vas deferens) and parts of the pharynx

^^ protection, absorption, and secretion ^^

transitional epithelial tissue

has many cell layers; cube-shaped and elongated cells; changes shape and appearance with increased tension; lines the urinary bladder, ureters, and part of the urethra 

^^ forms a barrier and lining that can be expanded ^^

glandular epithelial tissue

composed of cells that produce and secrete substances into ducts or boldly fluids → these cells are usually found in cuboidal or columnar epithelium

endocrine glands

__ secrete into the tissue fluid or blood

exocrine glands

__ secrete into ducts that open onto an internal or external surface

unicellular exocrine glands

composed of one epithelial cell, such as a goblet cell (secrete mucus)

multicellular exocrine glands

__ consisting of many cells; can be simple/compound (sweat&salivary)

simple exocrine glands

__ communicates with the surface by an unbranched duct, small and large intestine, and secretes mucus for digestion

compound exocrine glands

duct branches before it reaches the secretory portion, the parotid and salivary glands

tubular exocrine glands

consist of epithelial-lined tubes

alveolar exocrine glands

terminal portions form sac-like dilations, secrete into ducts, and milk from mammary glands

merocrine glandular secretion

secrete fluid products by exocytosis, salivary and sweat glands, pancreas (digestive juices into the duodenum)

apocrine glandular secretion

lose a small part of the cell during secretion; mammary and cerunious glands (earwax)

holocrine glandular secretion

releases entire cells filled with product, sebaceous glands

The Sebaceous Gland (holocrine)

secretes sebum, an oily substance on our skin, and is associated with a hair follicle. It is a simple-branched alveolar gland that secretes entire cells (overproduction can lead to acne)

connective tissues

what tissue is the most abundant tissue type by weight?

extracellular matrix

connective tissues contain abundant __ between cells, consisting of protein fibers and a ground substance

fibroblasts (fixed)

are the most common fixed cell and are large, star-shaped cells that produce fibers by secreting protein into the matrix

 ⬆Rapidly respond to injury by increasing in number → repair tissues that have limited abilities to regenerate

mast cells

are usually near blood vessels (immune system cells) that are derived from white blood cells; covered in granules; release heparin → prevents blood clotting; release histamine → stimulates inflammation and is a vasodilator

macrophages (wandering)

originate as white blood cells and are also known as histocytes; very numerous; usually attached to fibers, but can detach and wander; conduct phagocytosis and function as these scavenger cells that can remove foreign particles from tissues; defend against infection

fibroblasts

__ produce collagen, elastic, and reticular connective tissue fibers

collagen fibers

are grouped in long, parallel bundles; great tensile strength → can resist considerable pulling forces; flexible but only slightly elastic; found in ligaments (connect bone to bone) and tendons (muscles to bones)

elastic fibers

are composed of bundles of myofibrils embedded in elastin, a protein that branches, can stretch and return to its original shape, and is not as strong as collagen fibers. They are found in the vocal cords and the respiratory air passages

reticular fibers

are thin, branching fibers of collagen that form delicate, supporting networks found in the spleen and liver

areolar connective tissues

form thin, delicate membranes with cells being mainly fibroblasts, in a gel-like ground substance; in the subcutaneous layer; beneath most epithelia, where it nourishes nearby epithelial cells; binds skin to underlying organs, and fills the space between muscles

adipose fat tissue

is adipocytes that store fat droplets in cytoplasm; push their nuclei to one side; crowd out other cell types to become itself; cushions joints and some organs (kidneys), and lies just beneath the skin to insulate

white adipose tissue

store nutrients for nearby cells to use in the production of energy

brown adipose tissue

has cells that have many mitochondria to break down nutrients to generate heat to warm the body (babies have more of this)

rectiular connective tissues

is composed of a network of thin reticular fibers, like a filter; it supports the walls of internal organs, the walls of the liver and spleen (immune system)

dense regular connective tissues

consists of many closely packed, thick collagenous fibers, a fine network of elastic fibers, and fewer

dense irregular connective tissues

is thicker, with interwoven, more randomly organized fibers, which allow the tissue to sustain tension exerted from many different locations

^found in the dermis, periosteum (covers bone), perichodrium (covers cartilage), and encapsulated organs → nourishes and protects the other parts of the body

elastic connective tissues

consist of yellow elastic fibers in parallel strands or a branching network; collagenous fibers and fibroblasts between these fibers; attachments between vertebrae, within the walls of some internal hollow organs, such as large arteries, and  some portions of the heart (aorta, and the larger airways)

cartilage 

provides support, frameworks, attachments, and protection of underlying tissues, and forms structural models for many developing bones

hyaline cartilage

is the most common type; slippery and smooth so bones can move smoothly, fine collagen fibers in matrix, and ends of bones in joints, nose, respiratory passages, and between your ribs

elastic cartilage

 is the most flexible, due to elastic fibers in the matrix, and is in the external ear (larynx)

fibrocartilage

is very tough due to many collagen fibers; a shock absorber; intervertebral discs, pads (menisci) of the knee, and the pelvic girdle

bone

is the most rigid connective tissue (mineral salts) that supports and protects vital structures (cranial and thoracic cavities), produces blood cells, and forms attachment sites for muscles; it forms the skeleton.

compact bone

(osteocytes + matrix + haversian) canal forms cylindrical units called osteons. Osteocytes send out processes into canaliculi and share the blood supply

spongy bone

makes up the interior part of bones, consists of bony plates containing osteocytes, with space between them for marrow; it is lighter in weight than compact bone

blood

is composed of cells (red or white) and cellular fragments called platelets suspended in plasma, and most are formed in hematopoietic tissues located in red marrow

integumentary system

The skin and its accessory structures make up the

weight

The integumentary system is the largest organ by __

skin

The__ is also called the cutaneous membrane

epidermis

the outer / superfiical layer of the skin

dermis

The innermost layer of the skin that binds epidermis to the underlying tissue; it supplies nutrients to the epidermis

subcutaneous

beneath the dermis; the insulated layer that is not considered part of the skin

nutrients

The subcutaneous layer provides

stratified squamous epithelium

epidermis is the outer layer that is known as __

avascular

The epidermis is __ which gets its blood supply from the dermis

keratinocytes

epidermis cells are __

epidermis protects against __

water loss, harmful chemicals, mechanical injury, and pathogens

stratum corneum

__ is a part of the epidermis and is fully keratinized with dead cells and a barrier that is further away from the dermis (5th or outer layer)

stratum lucidum

__ is a part of the epidermis and is only found in the thickened skin of the palms and soles (4th layer from the inside dermis)

stratum granulosum

__ is a part of the epidermis and is the granular layer where keratinization begins (3rd middle layer)

stratum spinosum

__ is a part of the epidermis and is the thick layer that cells form from junctions (2nd inner layer)

stratum basale

__ is a part of the epidermis and is the deepest (1st or base) layer that cells go through mitosis (very active layer), starting point

dendritic cells

(Langerhans cells) that are found in the stratum spinosum and have phagocytes that protect the skin and underlying tissues from infections

tactile cells

(Merkel cells) are found in the stratum basale and are along with sensory nerve endings, and act as sensory receptors for light touch

melanocytes

They are found in the stratum basale and produce pigment melanin

absorbs UV light from sunlight and provides skin color

cytocrine secretion

Melanin is distributed to keratinocytes via granules, to protect from UV radiation → __

DNA

genetic material that has molecules that store information in its sequence of nucleotides, which instruct a cell on how to synthesize certain proteins

proteins coded

enzymes, blood proteins, structural proteins of muscles and connective tissue, antibodies, and cell membrane components are __ in DNA function

red blood cells

do not have DNA because of how small it is and how well it binds to hemoglobin!

Gene

part of a DNA molecule that encodes the information to synthesize a protein; the unit of inheritance

chromosomes

Long molecules of DNA and its proteins are organized into __

genome

complete set of genetic instructions for an organism → all cells contain two copies of the genome (except sex cells because you get one from mom, then one from dad)

exome

a small portion (2%) of the genome that codes for proteins

gene expression

control of which proteins are produced in each cell type, in what amount, and when

nucleotides

the structure of DNA is __ known as building blocks of DNA

nucleotides, complementary strands, and hydrogen

DNA is a double stranded-molecule consisting of 2 chains of __ and resembles a ladder twisted into a spiral with bases of 2 __ that are linked together by __ bonds

adenine —> thymine

cytosine —> guanine

complementary base pairing can look lke:

purines

adenine and guanin are __

pyrimidines

cytosine and thymine

histones

The DNA double helix is wound around proteins called __

chromatin

a group of 8 histones —>

synthesize proteins

the configuration of chromatin influences which genes are being acessed to __ under certain conditons

DNA Replication

is a process in which an exact copy of the DNA molecule is made; it occurs during interphase (S Phase)

base pairs

During DNA Replication, hydrogen bonds break in between __

DNA helicase

During DNA Replication, strands unwind and seperate (via __)

DNA Polymerase

During DNA Replication, new nucleotides pair with exposed bases, under the direction of __

sugar-phosphate backbone

During DNA Replication, DNA polymerase connects new __ that provide a template for complementary RNA —> hydrogen bonds