1. Tissues, Glands & Membranes
Chapter 4
Tissues, Glands & Membranes

2. Histology Is the study of body tissues
There are 4 ways body tissue is classified:
Epithelial Tissue – covers the surfaces of the body, lines cavities & forms glands
Connective Tissue – supports and forms the framework of all parts of the body
Muscle Tissue – contracts and produces movement
Nervous Tissue – conducts nerve impulses

3. Epithelial Tissue
Forms a protective covering for the body & all the organs
Example:
It is the main tissue of the outer layer of skin & it forms the lining of the intestinal tract, respiratory & urinary passages, blood vessels, the uterus & other body cavities

4. Structure of Epithelial Tissue
Epithelial tissue is classified according to its shape:
Squamous epithelial tissue is flat and irregular
Cuboidal epithelial tissue is square
Columnar epithelial tissue is long & narrow
Simple arrangement of cells is a single layer
Stratified arrangement of cells is many layered

5. Squamous Cells
Simple Squamous is a single layer of flat, irregular cells
Stratified squamous are many layered, flat, irregular cells

6. Cuboidal Cells
Simple cuboidal – single layer of square shaped cells

7. Columnar Cells
Simple columnar – single layer of long, narrow cells

8. What is Transitional Epithelium?
Because certain organs must vary a great deal in size during the course of their activities, they are composed of a specialized tissue called transitional epithelium
This specialized tissue is capable of expanding and returning to its original form
Examples of epithelial tissue are:
Urinary bladder >
Uterus

9. Functions of Epithelial Tissue
To produce secretions - Ex: mucous, perspiration & digestive juices
Absorption of digested food – done by special epithelium in the digestive tract
Trapping of dust and foreign particles in the passages of the respiratory system
Certain areas of the epithelium are capable of modifying themselves for greater strength – Ex: calluses
Reproduce frequently – Ex: skin, lining of the mouth & lining of the intestinal tract

10. Have many active cells made up of epithelial cells
Glands – are organs specialized to produce a substance that is sent out to other parts of the body
Have many active cells made up of epithelial cells
Glands are divided into 2 categories:
Exocrine Glands
Endocrine Glands

11. Exocrine Glands
Have DUCTS to carry secretions away from the gland – either to a body cavity or another organ
Ex: digestive juices, oil glands of the skin called SEBACEOUS glands & tears from the LACRIMAL glands

12. Endocrine Glands
Depend on the blood that flows through a gland to carry the secretion to another organ – these glands are DUCTLESS
These secretions are called HORMONES and have specific effects on tissues
Because they secrete directly into the bloodstream, they have an extensive blood vessel network – Ex: Adrenal Glands (near the kidneys) secrete epinephrine & adrenaline

13. Connective Tissue Is the supporting fabric for all parts of the body
Has large amounts of non-living material between the cells called MATRIX
Matrix contains: water, fibers & hard minerals
There are 4 types of connective tissue classified by the degree of hardness:
1. Soft 2. Liquid 3. Fibrous 4. Hard

14. Soft Connective Tissue
Loosely held together with a semi-liquid material between cells
Adipose (Fat) Tissue – contains cells capable of storing large amounts of fat which are used as a reserve energy supply, serve as a heat insulator & a protective padding for organs and joints
Areolar (Loose) Tissue – the most common type in the body which contains cells & fibers in a loose, jelly-like material; found in membranes around vessels & organs, between muscles & under skin

15. Liquid Connective Tissue
Suspended in a fluid environment
Ex:
Blood
Lymph (fluid that circulates the lymphatic system)

16. Fibrous Connective Tissue
Densely packed tissue with fiber cells called FIBROBLASTS
Examples:
Collagen – flexible, white protein that is the main type of fiber found in connective tissue
Capsules – a particularly strong form that makes up the covering around certain organs: kidneys, liver & glands
Tendons – connect muscle to bone and the fibers all run in the same direction
Ligaments – connect bone to bone and the fibers all run in the same direction

17. Repair of Fibrous Tissue
Can repair itself easily
Example:
Blood clots to form scabs to protect underlying tissue
From damaged capillaries, new vessels branch & grow to the injured tissue
Fibroblasts produce collagen & extensive growth of new tissue will form a scar
Excessive production of collagen may cause development of a KELOID

18. What is Keloid Scarring?
Keloid scarring is a sharply raised area on the surface of the skin
Parts of the body susceptible to keloids are the deltoid region of the upper arm, the upper back, and the sternum. The earlobes and the back of the neck are common sites as well.

19. Hard Connective Tissue
Made up of a firm consistency or actually hardened by minerals
Examples:
Cartilage – used as a “shock absorber” and a bearing surface because of its strength and flexibility
Bone – made up of OSSEOUS tissue, it is much like cartilage in its cellular structure but becomes solid and hard with the addition of calcium & phosphorus

20. Muscle Tissue
Designed to produce movement by contraction of its cells which are called MUSCLE FIBERS
Muscle tissue is not repaired easily, if at all, once an injury has been sustained
Muscle tissue is classified a follows:
Skeletal
Cardiac
Smooth

21. Skeletal Muscle Works with tendons & bones to move the body
Known as “voluntary” muscle
Moves or contracts by conscious thought

22. Cardiac Muscle
Forms the bulk of the cardiac wall called the MYOCARDIUM
Produces the regular contractions of the heart
Known as “involuntary” muscle
Moves or contracts independently of conscious thought

23. Smooth Muscle Also known as VISCERAL muscle
Forms the walls of the VISCERA, which are the organs of the ventral body cavity – except the heart – includes: muscles of the digestive tract, walls of the blood vessels & tubes that carry urine from the kidneys
Also attached to the base of each body hair – contraction of these muscles cause the condition called “goose bumps”

24. Nervous Tissue
Makes up the entire “communication” system of the brain, nerves and spinal cord

25. Neurons Basic unit of nervous tissue
Consists of a nerve cell body and fibers
Dendrites carry impulses TO the cell body
Axons carry impulses AWAY from the cell body
Axons are insulated & protected by the MYELIN SHEATH

26. Membranes
Thin sheets of tissue that can be fragile, tough, transparent or opaque
Cover surfaces, serve as dividing partitions, line organs or anchor organs
May contain cells that secrete lubricants, such as in the joints

27. Membranes & Disease A number of diseases directly affect membranes:
The Common Cold: Inflammation of the nasal passages
Peritonitis: Infection of the peritoneum commonly follows the rupture of the appendix which can be fatal if not treated in time

28. - Rheumatoid Arthritis – where the synovial membrane becomes inflamed and swollen affecting the cartilage in the joints
- Lupus – the serous membranes (pleura & pericardium) become inflamed, damaged and destroyed leading to a number of physical problems

29. Membranes usually protect against the spread of infection, but in some cases, can also act as a pathway to spread disease
In general, when a person’s resistance is lowered, infection can spread
For example, a pregnant female can develop an infection in the tubes of the reproductive system which could travel into the placenta and affect the unborn child

30. Benign & Malignant Tumors
Any abnormal cell growth is called a TUMOR or NEOPLASM
Benign tumors are typically confined to an area and do not spread
Malignant tumors spread to neighboring tissues or distant parts of the body
METASTASIS is the process of tumor cell spread

31. Benign Tumors
Although typically not life-threatening, they can be harmful in certain cases, such as growing within an organ, increasing in size and causing damage to the organ
Types of benign tumors include:
Papilloma: grows in epithelium, such as a wart
Osteoma: originates in the bones
Myoma: originates in muscle tissue; common mostly in involuntary muscle, particularly in the uterus (Fibroid Tumors)
Angioma: composed of small blood vessels; more commonly known as a birthmark
Nevus: skin tumors; better known as moles which are ordinarily harmless, but can become malignant

32. Papilloma – a common wart
Mastoid Osteoma – tumor of the bone behind the ear

33. Fibroid Tumor (Myoma)
Birthmark (Angioma)

34. Mole (Nevus)

35. Malignant Tumors Can cause death, no matter where they occur
Send out “claw-like” extensions into neighboring tissue
Cancer cells travel to other body parts fairly easy
Secondary tumors form or METASTASIZE
Grow more rapidly than benign tumors

36. Carcinoma Most common form of cancer
Originates in the epithelium which includes:
Skin
Mouth
Lung
Breast
Stomach
Colon
Prostate
Uterus
**Usually spreads by the lymphatic system

37. Sarcoma Cancer of the connective tissue
Can be found anywhere in the body
Usually spreads by the bloodstream

38. Gastric Lymphoma A lymphoma is a malignant tumor that arises from the lymphoid cells in the body. They can occur almost anywhere in the body, including the stomach. In this instance, the tumor is present in the upper portion of the stomach and appears as an irregular ball. (Carcinoma)
Kaposi’s Sarcoma

39. Cancer Symptoms Unusual bleeding or discharge Persistent indigestion
Chronic cough
Change in a mole
Sore that doesn’t heal
Presence of a lump
Unexplained loss of weight

40. Cancer Diagnosis Biopsy – removal of living tissue to examine cells
Ultrasound – high frequency sound waves to differentiate tissue
Computed Tomography (CT Scan) – cross sectional x-rays
Magnetic Resonance Imaging (MRI) – use of magnetic fields & radio waves to show changes in soft tissue
Blood Tests – screen the blood for key information; Example: Prostate Specific Antigen (PSA) test that screens for proteins produced in large quantities by prostate tumors

41. Cancer Treatment
Surgery – benign tumors are removed more easily. Malignant tumor surgery could leave cancerous tissue behind. Laser surgery can destroy the tumor or cut the tumor in order to remove it.
Radiation – destroys rapidly dividing cells with small doses of radioactivity
Chemotherapy – drugs called ANTINEOPLASTIC AGENTS act selectively on cancer cells