Chapter 4 Tissue Level Organization

Question 1

Define the term

TISSUE

Answer 1

A group of cells.

Has common embryonic origin,

Function together.

Question 2

Define

CONNECTIVE TISSUE

Answer 2

Protects and supports the body and its organs, binds or holds organs together as a unit, stores energy reserves for the body and provides immunity.

Question 3

Define

EPITHELIAL

Answer 3

Covers body surfaces (skin), lines hollow organs (stomach) or body cavities and ducts, and forms glands.

Question 4

Define

MUSCULAR TISSUE

Answer 4

Generates force and is responsible for movement.

Question 5

Define

NERVOUS TISSUE

Answer 5

Detects changes in the environment

Responds by intitiating nerve signals

Helps coordinate body activities and maintain homeostasis.

Question 6

Tight Junctions

Answer 6

Has web-like strands of transmembrane proteins that allow the lipid portions of adjacent cell membranes to be tightly bound together to prevent passage of water and solutes between cells. Example: stomach, bladder, intestines.

Question 7

ADHERENS (ANCHORING) JUNCTION

Answer 7

Has a dense layer of protein on the inner surface of the plasma membrane which serves as an attachment point for the cytoskeleton and transmembrane proteins, forming a very tight anchor, holding neighboring cells together.

Found in epithelial tissues lining ducts and hollow cavities.

Question 8

DESMOSOMES & HEMIDESMOSOMES

Answer 8

Very tight junctions that resist stretching or twisting of tissue.

Found between the layers of skin & between cardiac muscle cells of the heart.

Question 9

GAP (Communicating) JUNCTIONS

Answer 9

Formed by channel proteins thereby permitting small molecules to pass from one cell to another cell quickly and easily.

Found between the cells of the heart and skeletal muscles, intestines and some nerve tissue.

Question 10

EPITHELIAL TISSUE

Answer 10

1. Very little extracellular fluid (ECF)
2. Cells are arranged in continuous sheets in single or multi layers:
   -The top layer is the APICAL layer.
   -The bottom layer is the BASAL SURFACE layer.
3. The epithelial tissue lies on top and is firmly attached to the:
   -Basement Membrane
   (basal lamina & reticular lamina)
4. NO nerve supply
5. NO blood supply AVASCULAR.
6. The only tissue being constantly RENEWED in large amounts by cells undergoing mitosis.
7. General functions: Protection, Filtration, Secretion, Absorbtion and Excretion.

Question 11

Epithelium Layers

1. How many?
2. Name and description.

Answer 11

3 Layers

• Simple: Contains only one layers of cells. Found where diffusion, osmosis, filtration, secretion or absorption is needed.
• Pseudostratified: Contains only one layer of cells. Appears to have several layers. All cells are attached to the basement membrane but may not reach the surface. May have cilia and others may secrete mucus. Looks like a pull apart roll. Nucleus are located at different levels.
• Stratified: Two or more layers. Found where protection of underlying tissue is needed, or in areas where there is a lot of wear and tear.

Question 12

4 SHAPES OF EPITHELIAL CELLS

Answer 12

1. Columnar: Cells tht are rectangular in shape. Generally produce secretions, absorb substances and specialized ones may have cilia.
2. Cuboidal: Cells that are cube-shaped. Generally produce secretions & are used for absorbtion of substances.
3. Squamous: Cells that are flat, plate-like. They are thin, they are used for diffusion & filtration. If found in many layers they can act as protection.
4. Transitional: Cells that vary in shape. Can change shape from cuboidal to flat due to stretching, expansion or body movements.

Question 13

GLANDULAR EPITHILIUM

2 TYPES

Answer 13

Glandular epithelium: glands found throughout the body and are specialized for secreting substances.

1. Endocrine Glands: Secrete products directly into the blood stream to be distributed throughout the body. IE: adrenal glands, thyroid gland, pituitary gland…
2. Exocrine Glands: Secrete products into ducts which empty onto the surface of the body or into a hollow cavity within the body such as: parts of the digestive tract. Also: sweat or oil glands, skin, tear glands, salivary glands and gall bladder.

Question 14

CONNECTIVE TISSUE CHARACTERISTICS

Answer 14

1. Consists of 2 parts
   - Cells & extracellular matrix.
2. Space between the cells contains PROTEIN fibers in fluid, semi-fluid, gelatinous, fibrous or calcified ground substance.
3. Matrix supports cells, strengthens, binds and provides elasticity.
4. Has blood supply except for cartilage. VASCULAR.
5. Most abundant tissue in body.

Question 15

CONNECTIVE TISSUE FUNCTIONS

Answer 15

1. Binds together/supports and strengthens other tissue types (ligaments/tendons).
2. Protect and insulate internal organs.
3. Divides organs into smaller sections.
4. Help transport substances in the body (blood/lymph).
5. Major site of long term energy storage (adipose tissue).
6. Provides main site of our immune responses.

Question 16

1. Immature cells end in: _______
2. Mature cells end in: _________

Answer 16

1. …Blast
2. …Cyte

Question 17

Define

FIBROBLASTS

Answer 17

Cells that secrete the fibers and ground substance that forms the matrix of connective tissue.

Question 18

1. Catrilage tissue fibroblast is called:_______
2. Bone tissue fibroblast is called:__________

Answer 18

1. Chondroblasts
2. Osteoblasts

Question 19

MACROPHAGES

Answer 19

• Type of white blood cells that are able to eat bacteria by phagocytosis.
• May be fixed position or wandering.

Question 20

PLASMA CELLS

Answer 20

Type of white blood cells that secrete antibodies, are important to immune function.

Question 21

MAST CELLS

Answer 21

Found along blood vessels and secrete the chemical called HISTAMINE that dilates small blood vessels to stimulated localized inflammation.

Question 22

ADIPOCYTES

Answer 22

Cells that store triglycerides for energy reserves, shock absorption and thermal insulation.

Question 23

WHITE BLOOD CELLS

Answer 23

Found primarily in the blood (especially neutrophils), they can migrate into connective tissues to fight localized infections.

Question 24

An extracellular matrix component in connective tissue.

GROUND SUBSTANCE CHARACTERISTICS

Answer 24

1. Found between the cells & fibers that make up connective tissue.
2. Consists of:
   - Glycosaminoglycans (GAG) and Proteoglycans are complex combos of poysaccharides & proteins that trap water making the GS more jellylike.
   - Hyaluronic Acid: a viscous, slippery substance that binds cells together and lubricates joint surfaces.
   - Chondroitin Sulfate: provides support and adhesiveness in cartilage, bone, skin and blood vessels.

Question 25

An extracellular matrix component in connective tissue. FIBERS CHARACTERISTICS

Answer 25

1. Fibers are scattered throughout the matrix and function to strengthen and support connective tissue. 2. 3 Main types: 1. **Collagen Fibers**: very strong, resist pulling forces, not stiff and provide FLEXIBILITY to tissue. Frequently found in parallel bundles for added strenth, found in bone, cartilage, ligaments & tendons. 2. **Elastic Fibers**: smaller than collagen, provide strength. Can be stretched a lot without breaking & then return to normal shape. Found in lungs, skin, blood vessels. 3. **Reticular Fibers**: thinner than collagen and form branched networks that form the framework for soft organs (spleen & lymph nodes), provide support and strength. Form basement membranes for epithelial tissues.

Question 26

All mature connective tissues originated from?

Answer 26

Embryonic connective tissue called **MESENCHYME**.

Question 27

LOOSE CONNECTIVE TISSUE

Answer 27

Contains fibers that are loosely intertwined between cells. 3 Main Types: 1. **Areolar**: found in subcutaneous layer of skin, connect skin to underlying structures. 2. **Adipose**: contains cells called adipocytes that store triglycerides for energy reserves, insulation, shock absorption. 3. **Reticular**: contains reticular fibers that form framework for soft tissue organs like liver, spleen, lymph.

Question 28

DENSE CONNECTIVE TISSUE

Answer 28

Contains more numerous & thicker protein fibers, but fewer cells. 3 Main Types: 1. **Dense Regular**: contains fibers that are arranged in parallel patterns for strength. Found in tendons & most ligaments. 2. **Dense Irregular**: contains fibers that are arranged in an irregular arrangement and are found in areas where pulling forces are exerted in various directions, ie SKIN, Heart valves... 3. Elastic: contains predominately branching elastic fibers, allows tissues to recoil to original shape after stretching. Lungs, vocal chords etc.

Question 29

CARTILAGE CONNECTIVE TISSUE CHARACTERISTICS TYPES

Answer 29

**AVASCULAR**, reparis slowly. Contains chondrocytes that are located in spaces in the extracellular matrix called **LACUNAE** & are surrounded by dense network of collagen and elastic fibers embedded in a ground substance of chondroitin sulfate. Can endure more mechanical stresses, generally covered by a dense irregular connective tissue membrane called **PERICONDRIUM**. 3 TYPES: 1. **HYALINE**: most abundant, weakest type. Found at the ends of bones where the resilient gel of matrix reduces friction and absorbs shock at joint surfaces. (Sternal area) 2. **FIBROCARTILAGE**: strongest type. Collagen fibers arranged in bundles. Found in intervertabral discs between the bones of spinal column. Holds and cushions compression forces of spine. 3. **ELASTIC**: Consists of elastic fibers that allow structures to be flexible yet maintain shape. EAR, NOSE TIP etc.

Question 30

BONE TISSUE (OSSEOUS) CONNECTIVE TISSUE

Answer 30

1. Made of rings of hard matrix (called **LAMELLAE**), contain small spaces in matrix called **LACUNAE** that are filled with extracellular fluid and contain mature bone cells called **OSTEOCYTES**. 2. Calcium & phosphorus mineral salts in matrix give tissue its **HARDNESS**. 3. Collagen fibers give it **STRENGTH**. 4. Primary function: PROTECTION of underlying structures. Storage of CALCIUM & phosphorus. 5. **Contains RED bone marrow**: where red & white blood cells are produced. 6. **Contains YELLOW bone marrow** where adipose tissue is stored.

Question 31

LIQUID CONNECTIVE TISSUE

Answer 31

Contains fluid-like extracellular matrix with few protein fibers. 2 Main TYPES: 1. **Blood Tissue**: VASCULAR. contains liquid matrix called plasma with differend elements suspended in it: - **Erythrocytes**: red blood cells transports oxygen & carbon dioxide. - **Leukocytes**: white BC immunity & allergies - **Platelets** (thrombocytes): blood clotting. 2. **Lymph**: has extracellular fluid that resembles blood but contains far less protein. Enters lymphatic vessels where it eventually returns to blood stream. Contains many **LYMPHOCYTES** (a type of white blood cell).

Question 32

Define MEMBRANES List 4 types.

Answer 32

Flat sheets of pliable tissue that cover or line a part of the body. 1. Cutaneous 2. Mucous 3. Serous 4. Synovial

Question 33

CUTANEOUS MEMBRANE

Answer 33

Skin that covers outside of body. Consists of superficial layer of cells called epidermis and deeper layer of connective tissue called dermis. Keratinized stratified squamous.

Question 34

MUCOUS MEMBRANES

Answer 34

Line cavities that open directly with exerior of body (digestive, respritory, urinary & reproductive). Goblet cells secrete mucus that prevents cavities from drying out. Serves important in immunity as it traps and prevents bacteria from entering further into body.

Question 35

SEROUS MEMBRANE

Answer 35

Line cavites sealed within body, like pericardial, peritoneal cavities, pleural. Produce slippery fluid that allows organs to glide easily over each otehr without friction.

Question 36

SYNOVIAL MEMBRANE

Answer 36

Surround freely moveable joint spaces to produce fluid that lubricates and nourishes the hyaline cartilage. Prevents fluid from escaping the joint space.

Question 37

MUSCAL TISSUE 3 types

Answer 37

Specialized tissue for contraction & relaxation. Main functions: 1. Produce body movement 2. Maintain body posture 3. Generate heat

Question 38

SKELETAL MUSCLE

Answer 38

1. Generally attached to bones. 2. Cells appear striated. 3. Cylindrical shape. 4. **Multi-nucleated**. Nucleus near the outer membrane. 5. Cells arranged parallel to each other. 6. VOLUNTARY muscles.

Question 39

CARDIAC MUSCLE

Answer 39

1. Forms the bulk wall of the heart. Contractions result in pumping blood. 2. Striated cells. 3. Cylindrical shape but are BRANCHED. 4. One nucleus, centrally located. 5. Cells connected with numberous desmosomes and gap junctions in areas called intercalated discs. 6. INVOLUNTARY

Question 40

SMOOTH MUSCLE

Answer 40

1. Visceral muscle. 2. Found in walls of interanl hollow structures & organs. 3. Spindle shaped cells (thicker in center with pointed ends) 4. NON-Striated. 5. UNI-Nucleated. Single nucleus centrally located. 6. Gap Junctions 7. INVOLUNTARY

Question 41

Loose Connective Tissue **AREOLAR** Cells: Fibers: Ground substance: Forms what?

Answer 41

**Cells**: fibroblasts, macrophages, plasma cells, mast cells, adipocytes, few white blood cells. **Fibers**: collagen, elastic reticular **Ground substance**: hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratin sulfate. **Forms**: subcutaneous layer

Question 42

Looser connective tissue **ADIPOSE TISSUE** Cells Matrix Fibers Matrix ground substance Found where?

Answer 42

**Cells**: adipocytes **Matrix fibers**: small numbers of collagen & elastic fibers. **Matrix Ground substance**: glycosamino- & proteoglycans. **Found**: where areolar connective tissue is located. Contents of adipocytes get so big they push all the cytoplasm & nuclear material to periphery. Adipocytes take us most volume of tissue.

Question 43

Loose connective tissue **RETICULAR** Cells Fibers Ground substance Forms Found where

Answer 43

**Cells**: Reticular cells **Fibers**: Reticular fibers, form a meshwork. **Ground substance**; reticular substance extracellular fluid. **Forms** STROMA of liver, spleen, lymph nodes and helps bind together smooth muscle cells. **Found**: spleen, filters, lymph filters, removes bacteria.

Question 44

**DENSE REGULAR CONNECTIVE TISSUE** Cells Matrix fibers Ground substance Found where

Answer 44

**Cells**: fibroblasts appear in rows between fibers. **Matrix fibers:** bundles of collagen fibers arranged in parallel patterns. **Ground subst**ance: glycosaminoglycans and proteoglycans in very little amounts. **Found** in tendons and most ligaments.

Question 45

**DENSE IRREGULAR TISSUE** Cells Fibers Ground substance Found where

Answer 45

**Cells**: collagen fibers irregularily arranged **Fibers**: numberous collagen and elastin fibers **Ground substance**: moderate amounts of glycosamionglycans and proteoglycans **Found**: reticular layer of dermis, periosteum, perichondrium.

Question 46

Dense CT **ELASTIC CONNECTIVE TISSUE** Cells Matrix fibers Matrix ground substance Found

Answer 46

**Cells**: fibroblasts **Matrix fibers**: coarse parallel elastic fibers along with fibroblasts and collagen fibers **Matrix ground substance**: Elastic= frequent branching and fusion of elastic fibers. **Found**: elastic arteries, lung tissue.

Question 47

**Hyaline cartilage** Cells Matrix fibers Ground substance

Answer 47

**Cells**: chondrocytes **Matrix fibers**: cartilage **Ground substance:** a resilient gel **Found**: mostly surrounded by perichondrium. Most abundant cartilage in body.

Question 48

**Perichondrium**

Answer 48

A layer os dense irregular connective tissue that surround cartilage of developing bone. Has 2 layers: outer fibrous layer (has fibroblasts that produce collagenous fibers) and inner chonrogenic layer. Found around elastic cartilage, hyaline cartilage, fibrocartilage and articular cartilage.

Question 49

**FIBROCARTILAGE** Cells Matrix fibers Matrix ground substance Found where

Answer 49

**Cells**: chondrocytes **Matrix fibers**: collagen fibers **Matrix ground substance**; rich in proteoglycan **Found** in pubic symphysis, intervertebral discs.

Question 50

**BONE TISSUE** Cell Extracellular Matrix fibers: Ground substance Found

Answer 50

**Cells**: osteoblasts, osteocytes, osteoclasts **Extracellular matrix fibers**: collagen fibers **Solid ground substance** **Found**: bones Predominant component is calcium phosphate in form of hydroxyapatit crystals.