Exam 2

Three basic characteristics of connective tissue

1.Specialized cells (more than 1 cell type present)

2.Solid extracellular protein fibers

3.Fluid extracellular ground substance

What makes up the matrix of connective tissue

Fibers and ground substance

Functions of connective tissue

1.Establishing a structural framework for the body

2.Transporting fluids and dissolved materials

3.Protecting delicate organs

4.Supporting, surrounding, and interconnecting other types of tissue

5.Storing energy reserves, especially in the form of triglycerides

6. Defending the body from invading microorganisms

Three general categories of connective tissues

1. Connective tissue proper

2. Fluid connective tissues

3. Supporting connective tissues

Functions of connective tissue proper and examples

Connect and protect
(ex: Tendons and adipose tissue)

Functions of fluid connective tissues and examples

Transportation
(Ex: Blood and lymph)

Functions of Supporting connective tissues and examples

provides structural strength
(Ex: Cartilage and Bone)

Connective Tissue Proper Cell Populations

1.Fibroblasts
2.Fibrocytes
3.Adipocytes
4.Mesenchymal cells
5.Macrophages
6.Mast cells
7.Lymphocytes
8.Microphages
9.Melanocytes

Most abundant cell type found in all connective tissue proper

Fibroblasts

Which cell type secrete proteins and hyalurnan

Fibroblasts

Which cell type is second most abundant found in connective tissue proper

Fibrocytes

Functions of Fibrocytes

maintain fibers of connective tissue proper

Functions of adipocytes

energy reserve and cushions tissues/organs

What are mesenchymal cells?

Stem cells that respond to injury or infection

(Differentiate into fibroblasts, macrophages, etc. in response to injury or infection)

What are macrophages?

Large, amoeba-like cells of the immune system

Functions of macrophages

Eat pathogens and damaged cells

Two classes of macrophages

1.Fixed macrophages
2.Free Macrophages

Characteristics of Fixed macrophages

stay in tissue. Frontline defense, reinforced by free macrophages and other cells

characteristics of Free macrophages

migrate through tissue

Functions of mast cells

Stimulate inflammation after injury or infection

What do Mast cells release after injury or infection

Release:
1.histamine (dilates blood vessels)
*to stimulate local inflammation*

2.heparin (anticoagulant)
*to prevent blood clots in areas of slow blood flow*

\______ are leukocytes (white blood cells) that also contain histamine and heparin

Basophils

What are lymphocytes

Specialized immune cells in lymphatic (lymphoid) system

Some lymphocytes may develop into \_________ that produce antibodies

Plasma cells (plasmocytes)

What can stimulate some lymphocytes to become plasma cells?

Vaccines

Types of Microphages

1.Neutrophils
2. Eosinophils

what are microphages

Phagocytic white blood cells

Functions of Microphages

1.Moves through connective tissue in small numbers

2.Respond to signals from macrophages and mast cells and signals from site of infection

Characteristics of Melanocytes

Synthesize and store the brown pigment melanin

Function of melanin

gives tissue a dark color

where are melanocytes located?

In the eye and the dermis of the skin

What is the first connective tissue in embryos

Mesenchyme

Characteristics of mesenchyme

1.The first connective tissue in embryos
2.Gives rise to all other connective tissues
3.Are not found in adults (though many adult connective tissues do have mesenchymal stem cells for tissue repair)

function of mesenchymal stem cells in adults

tissue repair

Mucous connective tissue is also known as \_______

Wharton's Jelly

What is Mucous connective tissue and where is it found?

1.Loose connective tissue found in many parts of embryo, including umbilical cord
2.Not found in adults
3.Stem cells obtained from Wharton's jelly may have therapeutic applications

Characteristics of adipose tissue

1.Contains many adipocytes (fat cells)
2.Incapable of dividing in adults
3.Shrinks when nutrients are scarce, cell doesn't die, can regain size when nutrients plentiful

\_________ \______ around adipose tissue can divide and differentiate into adipocytes if there is chronic elevation of circulating lipids

Mesenchymal cells

Two types of adipose tissue

1. White Fat
2. Brown Fat

Functions of White fat

1.Most common
2.Stores fat
3.Absorbs shocks
4.Slows heat loss (insulation)

Functions of Brown Fat

1.more vascularized. Widespread in fetus and infants, only small amounts in adults

2.Adipocytes have many mitochondria

3.When stimulated by nervous system, fat breakdown accelerates, releasing energy as heat
*surrounding tissues absorb heat quickly and warms circulating blood*

Formed elements of blood

1.Red blood cells (erythrocytes)

2.White blood cells (leukocytes)

3.Platelets

Extracellular fluid includes:

1.plasma

2. interstitial fluid

3. lymph

Characteristics of lymph

1.Monitored by immune system
2.Transported by lymphatic (lymphoid) system
3.Returned to venous system (cardiovascular system

Functions of cartilage

for shock absorption and protection

characteristic of cartilage

Gel-type ground substance

Functions of Bone

For weight support

Cartilage is produced by what type of cell?

Chondrocytes

Chondrocytes produce \________________ which prevents the formation of new blood vessels

antiangiogenesis factor

Bone (osseous tissue) maintained by what type of cell?

Osteocytes

Characteristics of Bone

1.Strong (matrix of calcified calcium salt deposits)
2.Resists shattering (has flexible collagen fibers imbedded)

Four types of membranes

1.Mucous membranes
2.Serous membranes
3.Cutaneous membrane
4.Synovial membranes

Functions of Mucous Membranes

Line passageways that have external connections

where are mucouse membranes (mucosae) located?

In digestive, respiratory, urinary, and reproductive tracts

Membranes consist of

An epithelium supported by connective tissue

What is the Lamina propria

connective tissue component that supports the epithelial tissue superior to it

What are serous membranes composed of?

mesothelium supported by areolar tissue

functions of serous membranes

1.Line cavities not open to the outside
2.Are thin but strong
3.Have fluid transudate (serous fluid) to reduce friction

two layers of serous membrane

1.A parietal portion covering the cavity
2.A visceral portion (serosa) covering the organs

Three serous membranes

1. Pleura
2. Peritoneum
3. Pericardium

What is the cutaneous membrane

Is skin, on body surface

What layers does the cutaneous membrane consist of?

1. epidermis
2. dermis

functions of synovial membranes

1. Line moving, articulating joint cavities
2. Synoviocytes line the cavity and produce synovial fluid (lubricant)
3.Protect the ends of bones
4.Lack a true epithelium since epithelial cells:

Characteristics of synovial membranes

1.Develop within connective tissue

2.No basement membrane underneath

3.Gaps found between cells (allowing free movement of synovial fluid with capillaries in connective tissue)

What is Fasciae?

1.The body's framework of connective tissue

2.Layers and wrappings that support or surround organs

Three types of Fasciae

1. Superficial fascia (also known as the hypodermis)

2. Deep Fascia

3. Subserous Fascia

Functions of Superficial Fascia

provides insulation and padding

functions of deep fascia

resist multidirectional forces; bound to capsules around most organs, tendons, and ligaments

functions of subserous fascia

protects body cavity lining when muscles/muscular organs move

What tissue is specialized for contraction?

Muscle tissue

characteristics of Skeletal Muscle cells

1.Usually called muscle fibers
2.Voluntary control
3.Long and thin
4.Striated and multinucleated (contains many nuclei)
5.Do not divide
6.Low repair ability, however myosatellite (stem cells) can fuse with damaged muscle cells for repair

cardiac muscle cells are called

cardiocytes

characteristics of cardiac muscle tissue

1.Involuntary control

2.Striated, single nucleus

3.Form branching networks connected at intercalated discs*(gap junctions connect adjacent cells)*

4. Regulated by pacemaker cells

characteristics of smooth muscle cells

1.Nonstriated, single nucleus
2.Involuntary control
3.Small and tapered
4.Can divide and regenerate

Functions of Neural Tissue

1.Specialized for conducting electrical impulses (sends electrical signals to other cells through an elongated cell process called the axon)

2.Rapidly senses internal or external environment

3.Processes information and controls responses

4.Neural tissue is concentrated in the central nervous system (brain and spinal cord)

Two types of Neural Cells

1.Neurons- nerve cells
2.Neuroglia (or glia) - supporting cells

functions of neurons

perform electrical communication

function of neuroglia cells

repair and supply nutrients to neurons

what system is the largest in the body?

The integument

Two parts of the integument

1.cutaneous membrane (skin)
2. accessory structures

where do accessory structures of integument originate?

the dermis

three accessory structures of the integument

1. Hair
2. Nails
3. Multicellular exocrine glands

which systems is the integumentary system connected to?

1. cardiovascular system
(by blood vessels in dermis)

2. Nervous System
(by sensory receptors that detect stimuli for pain, touch, and temperature)

what type of connective tissue is the hypodermis composed of?

loose connective tissue

What seperates the integument from the deep fascia around organs?

hypodermis

five main functions of skin

1.Protection of underlying tissues and organs

2.Excretion of salts, water, and organic wastes (glands)

3.Maintenance of body temperature (insulation and evaporation)

4.Production of melanin, keratin, vitamin D3, and storage of lipids

5.Detection of touch, pressure, pain, and temperature

what type of epithelium is the epidermis composed of?

avascular stratified squamous epithelium

What is the most abundant type of epithelial cells?

keratinocytes

The five strata of keratinocytes in thick skin (from basal lamina to superior layer)

1.Stratum basale
2.Stratum spinosum
3.Stratum granulosum
4.Stratum lucidum (missing in thin skin)
5.Stratum corneum

the stratum basale layer is attached to basement membrane by \___________

hemidesmosomes

functions of Stratum basale

1.Forms a strong bond between epidermis and dermis
2.Forms epidermal ridges (basis of fingerprints)
3.Dermal papillae (tiny mounds)
*projections from Dermis*
4. has many basal cells (or germative cells)

functions of the Dermal papillae (tiny mounds)

1.Increase the area of basement membrane
2.Strengthen attachment between epidermis and dermis

Specialized cells of Stratum Basale

1. Merkel cells
2. Melanocytes

functions of Merkel cells

1. Found in hairless skin
2. Respond to touch (trigger nervous system)

What are Merkel cells?

Specialized epithelial tactile cells

functions of Melanocytes

1.Contain the pigment melanin
2.Scattered throughout stratum basale

characteristics of Stratum spinosum (spiny layer)

1.Produced by division of stratum basale
2.Eight to ten layers of keratinocytes bound by desmosomes
3.Cells shrink until cytoskeletons stick out (looks spiny)
4.Continue to divide, increasing thickness of epithelium
5.Contain dendritic (Langerhans) cells, active in immune response.

What are dendritic (langerhans) cells and their function?

1. active in immune response
2. *defend against microorganisms that get past superficial layers of epidermis and defend against superficial skin cancers*

Functions of Stratum Granulosum (grainy layer)

1. Stops dividing, starts producing:
Keratin and keratohyalin

What is keratin?

1.A tough fibrous protein
2. Makes up Hair and Nails

*Note: as keratin accumulates, the cell flatten and its plasma membrane thickens and becomes less permeable.*