PNB: transporters,tissues, and epithelia

What are the 4 major tissue types?

Epithelial, connective, muscle, nervous

What is a tissue?

Similar cells working together for a common purpose

What is an organ?

Different tissues working together for a specific function

What is epithelial tissue mainly made of?

Cells with very little extracellular matrix

What is epithelial polarity?

Having an apical top and basal bottom

What does the basal surface attach to?

Basement membrane

Is epithelium vascular?

No. It is avascular.

Can epithelial tissue regenerate?

Yes. Its cells readily divide by mitosis.

What are the 5 major epithelial functions?

Protection, selective permeability, movement, secretion, sensation

What does protection do?

Protects against dehydration, abrasion, and harmful agents

What does selective permeability mean?

Controls what passes across the epithelium

What does exchange mean?

Passive flow between compartments

What does transport mean?

Active or facilitated movement of solutes and water

What does movement or clearing mean?

Pushes material along a surface

What does secretion mean?

Releases substances such as sweat and saliva

What does sensation mean?

Detects stimuli through receptors connected to nerves

What is the function of cilia?

Move substances across a surface

What is the function of microvilli?

Increase surface area

What is an exocrine gland?

A gland with a duct

Where do exocrine products go?

To an exterior surface, such as skin or intestinal lumen

What is an endocrine gland?

A ductless gland

Where do endocrine products go?

Bloodstream or interstitial fluid

What is merocrine secretion?

Product released by exocytosis

What are examples of merocrine secretion?

Pancreas, sweat, saliva

What is apocrine secretion?

Part of the cell breaks off

What are examples of apocrine secretion?

Milk and underarm perspiration

What is holocrine secretion?

The whole cell is lost

What is an example of holocrine secretion?

Sebaceous or oil gland

What does a tight junction do?

Prevents substances from passing between cells

Where are tight junctions?

Near the apical surface

What does an adherens junction do?

Connects neighboring cells using actin

What is another name for an adherens junction?

Zonula adherens

What does a desmosome do?

Strongly ties cells together

What filaments do desmosomes use?

Intermediate filaments

What does a hemidesmosome do?

Attaches a cell to the basal lamina

What does a gap junction do?

Allows cell-to-cell communication

What protein makes gap junctions?

Connexin

What is a connexon?

A hemichannel made of 6 connexins

What is the most abundant tissue type?

Connective tissue

What is the main job of connective tissue?

Connect structures

What are examples of connective tissue?

Tendons, ligaments, fat, blood, bone, cartilage

What are the 3 components of connective tissue?

Cells, protein fibers, and ground substance

What are the 3 protein fibers?

Collagen, elastic, reticular

What is ground substance?

Proteins, carbohydrates, salts, and water

What makes up the ECM?

Protein fibers and ground substance

What does ECM stand for?

Extracellular matrix

Who produces the connective tissue matrix?

Connective tissue cells

What are the 6 functions of connective tissue?

Protection, support, binding, storage, transport, immunity

What connective tissue function holds structures together?

Binding

What connective tissue function is performed by blood?

Transport

What connective tissue function is performed by fat?

Storage

What are the 3 major connective tissue categories?

Proper, supporting, fluid

What does connective tissue proper divide into?

Loose and dense

What does supporting connective tissue include?

Cartilage and bone

What does fluid connective tissue include?

Blood

Does loose connective tissue have more or fewer fibers?

Fewer fibers

Does loose connective tissue have more or less ground substance?

More ground substance

What is an example of loose connective tissue?

Adipose or fat

Does dense connective tissue have more or fewer fibers?

More fibers

Does dense connective tissue have more or less ground substance?

Less ground substance

What are examples of dense connective tissue?

Tendons and ligaments

What does a tendon connect?

Muscle to bone

What does a ligament connect?

Bone to bone

What type of connective tissue are tendons?

Dense regular connective tissue

Why are tendons dense regular connective tissue?

Collagen fibers are parallel

What type of matrix does cartilage have?

Semisolid

What type of matrix does bone have?

Solid

What type of tissue is blood?

Fluid connective tissue

What type of matrix does blood have?

Liquid

What are erythrocytes?

Red blood cells

What is the main job of RBCs?

Gas exchange

What are leukocytes?

White blood cells

What is the main job of WBCs?

Immunity

What do platelets do?

Blood clotting

What is the main protein in blood?

Albumin

What is plasma?

Watery ground substance

What are muscle cells called?

Muscle fibers

What do muscle fibers do when stimulated?

Contract or shorten

What does muscle contraction produce?

Movement

What can muscles move?

Bones, blood, and food

What are the 3 muscle types?

Skeletal, cardiac, smooth

Which muscle types have striations?

Skeletal and cardiac

Which muscle type lacks striations?

Smooth

What special structure is found in cardiac muscle?

Intercalated discs

What is a cardiac muscle cell called?

Cardiac myocyte

What is a smooth muscle cell called?

SMC

What are the 2 nervous tissue cell types?

Neurons and neuroglia

What is another name for neuroglia?

Glia

What do neurons do?

Conduct electrical activity

What do glia do?

Support neurons

What is the main function of nervous tissue?

Rapid communication and control

What part of a neuron receives input?

Dendrites

What part of a neuron contains the nucleus?

Cell body

Where does the axon begin?

Axon hillock

What carries the output signal?

Axon

What covers parts of the axon?

Myelin sheath

What is at the end of the axon?

Axon terminal

What is the communication point between neurons?

Synapse

What is the gap at a synapse?

Synaptic cleft

Which tissue has extensive matrix?

Connective tissue