TISSUES

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Cells Tissues Organs Organ systems Organism

Cells are not found by themselves; they’re with others. These are called tissues.

TISSUE: A group of cells, usually similar, which share a particular function.

ORGAN A group of tissues which share a particular function.

ORGAN SYSTEM: A group of organs which share a particular function (digestive system, nervous system).

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Cell Differentiation

Through the process of cell differentiation, each cell develops a characteristic set of structural features.

Each cell has to contribute one piece toward the overall function of the organism, so that all the vital functions can be covered.

During differentiation, cells in nearby locations become able to work together.

After differentiation, cells do not change their function throughout their life cycle

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Specialized Structures on some tissues

Microvilli

Cilia

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Microvilli

The presence of large numbers of microvilli on the exposed surfaces of epithelial cells indicates that this is the area where absorption and secretion take place.

These cells are transportation specialists.

They are probably located along portions of the digestive and urinary tracts

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A Cilium

Figure 4.8

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TYPES OF TISSUES EPITHELIUM: a sheet of cells that makes up the

surface of the skin and also lines tubes in the body.

CONNECTIVE TISSUE: deep to the epithelium; supplies oxygen and nutrients to epithelium.

Fibrous (Proper) Connective Tissue Special Connective Tissue (cartilage, bone, blood,

muscles, nerves)

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SIMPLE EPITHELIUM

SIMPLE EPITHELIUM has only one cell layer.

SIMPLE SQUAMOUS EPITHELIUM:

SIMPLE CUBOIDAL EPITHELIUM

SIMPLE COLUMNAR EPITHELIUM

PSEUDOSTRATIFIED EPITHELIUM

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STRATIFIED EPITHELIUMSTRATIFIED EPITHELIUM has more than one cell layer. The

type of epithelium is named by the APICAL layer.

STRATIFIED SQUAMOUS EPITHELIUM:

1) Keratinized stratified squamous epithelium

2) Non-keratinized stratified squamous epithelium  

STRATIFIED CUBOIDAL EPITHELIUM

STRATIFIED COLUMNAR EPITHELIUM

TRANSITIONAL EPITHELIUM

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FIBROUS (PROPER) Connective tissues

FIBROUS (PROPER) Connective tissuesADIPOSE (fat)RETICULAR (lymph nodes)LOOSE (aka AREOLAR; upper dermis)DENSE

REGULAR (tendons and ligaments) IRREGULAR (lower dermis and joint capsules)

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Special Connective TissueSpecial Connective Tissue

Cartilages Hyaline cartilage (most joints) Elastic cartilage (ear) Fibrocartilage (intervertebral discs)

Bone tissues Compact bone (shaft of long bones) Spongy bone (ends of long bones)

BloodMuscles (discussed more in later lectures)Nerves (discussed more in later lectures)

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Disorders of Adipose

Lipoma

Liposarcoma

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Lipoma

These are benign fat nodules in the hypodermis, usually associated with high cholesterol levels. They are easily surgically excised (removed)

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LiposarcomaPatients usually note a deep

seated mass in their soft tissue. Only when the tumor is very large do symptoms of pain or functional disturbances occur.

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Most frequent in middle-aged and older adults (age 40 and above), liposarcomas are the second most common of all soft-tissue sarcomas . Annually 2.5 cases occur per million population.The prognosis varies depending on the site of origin, the type of cancer cell, the tumor size, the depth, and proximity to lymph nodes. Well-differentiated liposarcomas treated with surgery and radiation have a low recurrence rate (about 10%) and rarely metastasize.

Why you got fathttp://www.youtube.com/watch?v=mNYlIcXynwE

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Fat to Water RatioAre you more drunk than you

think?, http://fxn.ws/TqUdz9

Women have a higher fat-to-water ratio than men do.

A 150-pound man holds more water than a 150-pound woman; after one drink, the woman will have a higher concentration of booze in her blood. That leads to greater intoxication. And her liver has to work harder to metabolize that alcohol, prolonging her buzz. 

For every drink a woman has, it’s the equivalent of a drink and a half for a same-sized man.

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Collagen

COLLAGEN

This is a type of fiber that is found in all connective tissues (other than blood).

It gives connective tissues an elastic consistency.

It has very little blood supply, so it does not regenerate well.

It does not interfere with diffusion of materials from one area to another; it just provides support for connective tissues.

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Collagen fibers18

Collagen

NOTE: If you get injured, you’d rather break a bone than tear a ligament, why?

The number of fibroblasts is the same, but the ligament has a lot more collagen to be made by each fibroblast.

And the blood supply to bone is much better than a ligament.

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Collagen Disorder

Scleroderma

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Scleroderma Scleroderma is a chronic systemic autoimmune disease (primarily of the

skin) characterized by fibrosis (or hardening), vascular alterations, and autoantibodies. There are two major forms:

Limited systemic sclerosis/scleroderma involves cutaneous manifestations that mainly affect the hands, arms, and face. It was previously called CREST syndrome in reference to the following complications: Calcinosis, Raynaud's phenomenon, Esophageal dysfunction, Sclerodactyly, and Telangiectasias. Additionally, pulmonary arterial hypertension may occur in up to one-third of patients and is the most serious complication for this form of scleroderma.

Diffuse systemic sclerosis/scleroderma is rapidly progressing and affects a large area of the skin and one or more internal organs, frequently the kidneys, esophagus, heart, and lungs. This form of scleroderma can be quite disabling. There are no treatments for scleroderma itself, but individual organ system complications are treated.

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GranulomaA granuloma is an inflammation found in many

diseases. It is a collection of immune cells known as macrophages.

Granulomas form when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate.

Such substances include infectious organisms such as bacteria and fungi as well as other materials such as keratin and suture fragments.

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Lightning Strike

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Types of Membranes

Synovial

Mucous

Serous

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Synovial MembranesThis membrane lines the inside of fluid-filled

joints.

The cellular layers are incomplete, with gaps between adjacent cells to allow the fluid to escape into the joint to serve as a cushion.

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Mucous Membranes

Mucous membranes are covered in epithelium, which are involved in absorption and secretion.

They line cavities that are exposed to the external environment and internal organs.

They are located at the nostrils, the mouth, the lips, the eyelids, the ears, the genital area, and the anus.

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Serous MembranesSerous membranes secrete a watery fluid.

The fluid reduces friction from muscles or organs rubbing against each other. Its major function is to produce tiny amounts of watery liquid on their opposing surfaces to reduce friction.

The serous membrane covering the heart is the pericardium. Inflammation here is called pericarditis.

The serous membrane surrounding the lungs is the pleura. Inflammation here is called pleuritis.

The serous membrane lining the abdominal cavity is the peritoneum. Inflammation here is called peritonitis.

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Another way to classify epithelium

1. MOIST EPITHELIUM: there are two types:

a. MUCOSA is the cell type that produces mucous. Therefore, pseudo-stratified columnar epithelium is a mucous epithelium, or a mucosa.

b. SEROSA is an epithelium that has watery secretions on the surface. This is found in sweat glands.

2. DRY EPITHELIUM is keratinized stratified squamous epithelium.

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Types of Glands

Exocrine GlandSecretes substances into a duct (a tunnel) and then

excretes it into the lumen or onto the skin (e.g. sweat, oil)

Endocrine GlandSecretes substances into the blood to be transported

to another part of the body, where it is used (e.g. hormones). Endocrine glands are ductless. We will discuss endocrine glands in a separate lecture.

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Exocrine Glands

Classification of Exocrine GlandsType of secretionMethod of secretionStructure

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Exocrine Glands

EXOCRINE GLANDS

1. Classified based on the type of secretion

a. SEROUS GLANDS secrete water, as found in sweat glands.

b. MUCOUS GLANDS secrete mucous, as found in goblet cells

c. MIXED GLANDS secrete mucous and water as found in salivary glands.

d. OIL GLANDS secrete waxy and oily substances, as found in sebaceous glands and ear wax.

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Glands

2. Classified by the method of secretion

Merocrine (Eccrine) glands

Apocrine glands

Holocrine glands

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Merocrine Gland Exocytosis

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2. Classified by the method of secretiona. MEROCRINE (Eccrine) GLANDS produce a secretion by a process called EXOCYTOSIS. Example is sweat gland

Cell of merocrine gland

Vesicle with green secretion inside

The vesicle moves to and binds with the cell membrane, pops open and releases the secretion

Merocrine Gland Functions

Thermoregulation

Inhibiting the growth of bacteria on the skin

Excretion of water, electrolytes, and some drugs

They do not function as a lubricant for the skin.

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Apocrine Glandsb. APOCRINE GLANDS accumulate material in the apical section, the top of the cell breaks off, and the material is released. The cells that broke down will grow again. Examples are the mammary glands and oil glands associated with pubic/axillary hairs.

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Holocrine Glands

c. HOLOCRINE GLANDS are those where the entire cell breaks off with all the contents inside, such as sebaceous (oil) glands. After the cell breaks off, the other cells move in quickly and close up the gap.

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Exocrine Glands

3. Classified by their structure (what they look like)

a. UNICELLULAR GLANDS, for example a GOBLET CELL.

Goblet cells are found in the trachea and secrete mucous to trap debris; then you cough it up.

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GOBLET CELL38

Glandsb. MULTICELLULAR GLANDS

Alveolar

Simple alveolar

Compound alveolar (mammary glands)

Tubular

Simple tubular (sweat glands)

Compound tubular

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Multicellular Glands

Alveolar Tubular

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Types of Multicellular Exocrine Glands

Figure 4.6

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Brown Recluse Spider

They like dark spaces & woodpiles. Also cool areas in the attic

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Day 3

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Day 5

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Day 6

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Day 9

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Day 10

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Brown Recluse Spider

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Get a Venom Extractor Kit

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Get a Venom Extractor Kit

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