tissues CH4

define tissues

group of cells with a common embryonic origin that function together to carry out specialized activities

4 basic types if tissue

connective, nervous, muscle, and epithelial

cell junctions

contact points between cells that hold cells together

which junctions are for connecting neighbouring cells?

tight, gap, desmosomes, adherens

what junction anchors to the environment?

hemidesmosomes

tight junctions

bind to protect spaces inbetween cells, often waterproof found in lining of stomach, intestines, and bladder

adhering junctions

adhesion belt connects to cytosol of cell, gives structure

desmosomes

similar to adhering, but its microfilaments extend further into the cytosol, bound to cytoskeleton

examples include the epidermis of the skin

hemidesmosomes

has integrin instead of cadherins, strong attachment anchoring to basement membrane (made out of protein/carbs). found in tissue that undergo friction and abrasive force

gap junctions

cells able to share cytoplasm, it has open communication channel through connexons which are small gaps that electrical impulses can go thru. ex. cardiomyocytes which contract simultaneously

epithelial vs connective tissues

epithelial cells tightly binded, packed. (high extracellular material)

connective cells more spaced out (low ECM)

epithelial tissues description

-sheets, densely packed (MANY junctions)

-attach to basement membrane

-frequent divis.

-avascular, w/ nerve supply

layer arrg. of epithelial tissue

simple-one layer

pseudostratified-onelayer, cells long, making layer thick

stratified-layered

Different cell shapes

cuboidal, squamous (flat), columnar (rectangular)

simple squam. ep.

superthin, ideal for filtration and diffusion (vessels, alveoli, eardrum)

simple cub. ep.

cuboidal=good at secretion and absorption ex. ovary surface, small ducts in glands

nonciliated simple colum. ep.

secretion/absorption (ex.line gastrointestinal tract and secrete mucus lining)

ciliated simple colum. ep. locations

in respiratory system, cilia beat to move mucus toward throat, or oocytes (egg cell) thru fallopian tube/oviduct/

ciliated pseudostrat. colum. ep.

line airway, trap particles, sweep mucus away from body

noncilated pseudostrat. colum. ep.

line epididymis, absorption and secretion

urothelium

stretchy, variable shape. lines bladder, ureters and yrethra

exocrine vs endocrine glandular ep.

and give example glands

endocrine secrete hormones that enter interstitial, then diffuse into bloodstream. ex. thyroid, adrenal, pancreas

exocrine secretions empty onto surfaces (skin) or hollows (lumen of stomach) for ex. sweat, oil, pancreas, salivary

ground substance

water and org. molecules, inbetween connective tissue cells, provide support

excitable cells, tissues containing them

neurons, muscle fibers- ability to respond to stimuli by elctrcl signals, presence of voltage gated channels

muscle tissue

motion posture heat

skeletal muscle tissue sf

superlong twizzler (30-40cm) multi-nucleated attached to bones by tendons, voluntary motion posture heat, protection

smooth muscle tissue sf

involuntary controls-motion, thin cells stratified

cardiac muscle tissue sf

pump blood, puzzle piece shape? involuntary-stimulates itself

nervous tissue

neurons and neuroglia, conducts nerve impulses

connective tissue- 2 elements and description

2 elements: connective tissue cell and extracellular matrix (ground substance and fiber)

no free surfaces

highly vascularized with nerve supply (except cartilage and tendons)

fibroblast

cell that secrete fiber and ground substance

macrophages

cells that eat bacteria and cell debris by phagocytosis

adipocytes function, location

fat cells that store fat and energy, it helps with insulation

found underneath skin and around heart and organs

mast cells

produce histamine- dilates blood vessel, kills bacteria and very abundant in blood vessels

neutrophils

WBC that are first to respond to foreign substances in the blood

eosinophil

wbc that respond to parasites and allergies

plasmocytes

comes from B-cell, secrete antibodies

2 embryonic connective tissue

mesenchyme conn. tissue -forms almost all other types of conn. tissue

mucoid (mucous) -umbilical cord

mature connective tissue

connective tissue proper- loose and dense

supporting conn. tissue- cartilage and bone

liquid conn. tissue- blood

hyaline cartilage

-rubbery gel, blue/white shiny

-found at the end of long bones, nose, super abundant

-provides smooth surfaces for joints, flexibility and support

-can be damaged

fibrous cartilage material, location, function

-thick bundles of collagen fibers

-intervertebral discs, menisci of knee, pubic symphysis (hip bones)

-rigid support and joining structures together, strongest cartilage

elastic cartilage

-elastic fibers

-external ear

-provide strength and elasticity, maintain shape

bone function and structure

-spongy but compact, make up many bones on body

-offer support, protection, storage (calcium can be extracted)

-houses blood forming tissue

blood

-only liquid connective tissue, no fiber in ecm

-consists RBC, WBC, platelets, plasma

-found in blood vessels and chambers in heart

-RBC carry oxygen/CO2 and nutrients, platelets for clotting, immune response

skeletal muscle

long cylindrical shape, longest muscle, used for movement, heat, posture

attaches to bones by tendons

cardiac muscle, location, describe and function

located at wall of heart.

stimulates itself, involuntary control

function is to pump blood across all parts of body

smooth muscles, functions, locations

involuntary control

functions for motions of organs that constrict and contract

found in hollows of structures such as stomach, bladder, blood vessels, intestines, airway to lung, uterus

nervous tissue (2 cells and their function)

neurons

-carry sensory and motor signal info, transmits signal

neuroglia

-support and protect neurons