Chapter 4: Introduction to Tissues

Question 1

4 basic categories of tissues

Answer 1

• Epithelial Tissue: covers and lines all body surfaces/cavities and are the major tissues of glands
• Connective Tissue: connects all other tissues in the body to one another
• Muscle Tissue: cells that can contract & generate force.
• Nervous Tissue: cells that can generate, send, and receive messages

Question 2

Epithelial Tissue

Answer 2

Epithelial Tissue: covers and lines all body surfaces/cavities and are the major tissues of glands
- Function: covers/protects, absorbs, secretes, filters

Question 3

Connective Tissue

Answer 3

Connective Tissue: connects all other tissues in the body to one another
- Function: support, protection, insulation, transportation

Question 4

Muscle Tissue

Answer 4

cells that can contract & generate force.

- Function: movement

Question 5

Nervous Tissue

Answer 5

cells that can generate, send, and receive messages

- Function: control & communication

Question 6

Extracellular Matrix (ECM)

Answer 6

composed of the substances in a tissue outside the cell that consists of extracellular fluid, ground substance, & protein fibers.

Question 7

Cell junctions

Answer 7

cells in tissue that are often linked to one another by integral proteins in neighboring cells that form structures.
-Attach cells

Question 8

Tight junctions

Answer 8

intercellular junction that holds cells tightly together in tissue and make the space between them relatively impermeable to water and many solutes (interweave/lock together like a zipper).

• Function: keep things from moving between cells
• between cells of blood vessels (prominent where the prevent substances from leaving the blood)

-nonfunctional: allow fluid/solutes in blood to leak out of the vessel into the ECF & the function of the epithelia as a barrier would be impaired

Question 9

Desmosomes

Answer 9

intercellular junction that hold cells together in a tissue to increase the tissues resistance to mechanical stresses (acts more like a button).

• Function: strength
• Epithelia of skin (prominent in cells with lots of mechanical stress)

-Nonfunctional: skin would not be resistant to mechanical stresses & could break down easily since cells can’t stick together well under stress

Question 10

Gap junctions

Answer 10

intercellular junctions that connect the cytosol of neighboring cells and allow water and solutes to pass between cells. Function: allow cells to talk
- Cardiac muscles (prominent in cells that can communicate w/ electrical signals)

• Nonfunctional: cells would lose a means of communication with each other, since gap junctions allow rapid communication

Question 11

Epithelial tissue

Answer 11

a tissue type composed of epithelial cells and a thin basal layer of ECM; function to cover/ line all body surfaces and hollow organs. Primary acts a barrier between the body and the external environment and between our organs and fluid-filled cavities.

• Avascular/ attached to basement membrane / always have a free surface
• Absorption, Secretion–>passive or active transport

Question 12

Structure of Epithelial tissues

Answer 12

Apical Surface(top): the “free edge” of an epithelial cell/tissue

Basal Surface(bottom): the edge attached to the deeper cells

Basement membrane: two layers of ECM- basal lamia and reticular lamina- that anchor an epithelial tissue to the underlying connective tissue.

Question 13

Number of cell layers

Answer 13

Simple Epithelia: type of epithelia tissue composed of only a single layer of cells and the underlying basal lamina

Stratified Epithelia: type of epithelia tissue composed two or more layers and the underlying basal lamina

Question 14

Shape of Epithelia cells

Answer 14

Epithelia cells can take on THREE basic shapes. The shape of the nucleus reflects the shape of the cell.

• Squamous Cell: flattened. Fast absorption & diffusion
• Cuboidal Cell: short (wide as they are tall). Absorb nutrition & produce secretions
• Columnar Cell: column shape that is tall & elongated. Absorb nutrition & produce secretions

Transitional: shape of its cell represented a “transition” between cuboidal and squamous cells

Question 15

Simple Squamous Epithelia:

Answer 15

diffusion transport can occur rapidly/easily of oxygen, carbon dioxide, fluids & ions.
Located: pleura, lining blood vessels
Function: Filtration & diffusion

Question 16

Simple Cuboidal Epithelia:

Answer 16

some passive transport but mostly active transport.
Located: kidney & thyroid glands,
Function: absorption & secretion of mucus and other substances

Question 17

Simple Columnar Epithelia

Answer 17

usually located in stomach, small intestine, gallbladder & kidney tubules

• Function: Absorption and secretion

Question 18

Pseudostratified Columnar Ciliated Epithelia

Answer 18

epithelia cells touching the basement membrane, but not all cells reach the apical surface

-Function: located in trachea/airway; moves mucus across cell surface, protection

Question 19

Stratified squamous Epithelia:

Answer 19

located in vagina/esophagus/anus/mouth/throat. nonkeratinized or keratinized (top layer is still living)

-Function: protection from mechanical stresses

Question 20

Transitional Epithelia

Answer 20

consisting of multiple layers of epithelial cells that can contract & expand. Tissue can stretch
-Urinary bladder, ureters, urethra

Question 21

Glandular Epithelium

Answer 21

makes and secretes a particular product (classified by shape & how they release their products)
Exocrine glands & endocrine glands

Question 22

Exocrine gland

Answer 22

A gland that secretes a product through a duct to the external surface (apical) of the body or into a hollow organ that opens to the outside of the body (respiratory/ gastrointestinal/ genitourinary tract).
Secretions have local actions–>only affects the cells in their general vicinity
Example: sweat glands/ salivary glands

Question 23

Endocrine gland

Answer 23

A gland that secretes hormone(s) directly into the bloodstream or extracellular fluid to influence the functions of distant target cells (cell-cell communication)

Question 24

Areolar(loose) Connective Tissue

Answer 24

spread fibers results in loose connective tissue.

-Location: Capillaries & nerves, hollow organs

Question 25

Dense Regular Connective Tissue:

Answer 25

thick collagen fibers arranged parallel to one another to form bundles, resist stress well in only ONE direction, all lined up together. -Location: Tendon & ligament

Question 26

Dense Irregular Connective Tissue

Answer 26

irregular bundles of collagen fibers, the organization makes it strong and allows it to resist tension in all three planes. Location: Dermis, around joints & organs

Question 27

Adipose(fat)Connective Tissue

Answer 27

made of adipocytes; stores fats. Function: insulation, warmth, shock absorption, protection, & cushioning, energy reserve

Question 28

Reticular Connective Tissue

Answer 28

net like tissue that is produced by surrounding fibroblasts Location: lymph nodes & spleen,

Question 29

Specialized Connective Tissues

Answer 29

more specific functions than connective tissue proper 1. Blood 2. Bone 3. Cartilage

Question 30

Blood Connective tissue

Answer 30

the fluid connective tissue consisting of formed elements and plasma Erythrocytes: (red blood cells) bind & transport oxygen Leukocytes: (white blood cells) immune cells Platelets: blood clotting

Question 31

Cartilage Connective Tissue

Answer 31

its tough, flexible tissue that absorbs shock & is resistant to tension, compression, shearing forces. It’s found in joints between bones, ears, nose, and certain respiratory passages. -avascular -Cells are found in lacunae and has chondrocytes Hyaline Cartilage: most abundant, smooth surface for joints, structural support (airway/rib cage), growth plates Elastic Cartilage: located in two places; Ear & epiglottis. Flexible Fibrocartilage: found in body that needs to resist stress. Vertebral, meniscus, disc in jaw, separator of pubic bone

Question 32

Bone Connective Tissue

Answer 32

hard matrix (deposits of Ca++ salts and lots of collagen) (looks like tree trunk) - Function: support, protection, storing calcium slats, housing bone marrow - Mature bone tissue contains three cell types: Osteoblasts: Bone builders Osteocytes: mature bone; monitors & maintains Osteoclasts: break down bone

Question 33

Nervous Tissue

Answer 33

makes up the majority of the brain, spinal cord, & nerves

Question 34

Two Major Nervous Cell Types

Answer 34

Neurons: generate, conduct, & receive information in the form of electrical signals called nerve impulses Neuroglia: supportive cell that anchor neurons and blood vessels in place; much smaller cells surrounding neurons -Purpose: anchors neurons and blood vessels in place, monitors the composition of the ECF., speed up the rate of nerve impulse transmission, & circulates the fluid that surrounds the brain and spinal cord

Question 35

Basic Structure of Neuron

Answer 35

``` Cell Body(soma): central portion of neuron that contains the nucleus & bulk of the organelles. - Function: Receives signals, it’s the main metabolic & nutritional center of the cell as well ``` Axon: a single extension “arm” of a neuron - Purpose: moves nerve impulse AWAY from the cell body to target cell (cell-cell communication) Dendrites: the other “arm” radiating from the cell body; typically, short & highly branched. - Purpose: receive messages from the axons of other neurons & BRINGS impulses to the cell body

Question 36

Serous Membrane (serosae)

Answer 36

lines cavities that do not open to the outside such as the pleural, pericardial, and peritoneal body cavities. Secretes serous fluid (thin/watery fluid) Parietal Layer: outer layer, it’s in contact w/ body wall Visceral layer: inner layer, covers the organs within cavity -Purpose: reduce friction-->lubrication

Question 37

Mucous Membrane (mucosae)

Answer 37

lines all body passages as part of the walls of hollow organs that open to the outside of the body, including respiratory passages, mouth, nasal cavity, digestive tract, & the male/female reproductive tracts. Secretes mucus (made by goblet cells) -Purpose: protection