Human Tissues Tissue differentiation. Tissue Types Muscle Epithelial Connective Nervous.
1 Chapter 4 Tissues, Glands & Membranes. 2 Histology Is the study of body tissues There are 4 ways...
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Transcript of 1 Chapter 4 Tissues, Glands & Membranes. 2 Histology Is the study of body tissues There are 4 ways...
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Chapter 4Tissues, Glands & Membranes
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Histology Is the study of body tissues
There are 4 ways body tissue is classified:
Epithelial TissueEpithelial Tissue – covers the surfaces of the body, lines cavities & forms glands
Connective TissueConnective Tissue – supports and forms the framework of all parts of the body
Muscle TissueMuscle Tissue – contracts and produces movement
Nervous TissueNervous Tissue – conducts nerve impulses
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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
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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
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Squamous Cells
Simple Squamous is a single layer of flat, irregular cells
Stratified squamous are many layered, flat, irregular cells
0
100
1stQtr
2ndQtr
3rdQtr
4thQtr
East
West
North
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Cuboidal Cells
Simple cuboidal – single layer of square shaped cells
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Columnar Cells
Simple columnar – single layer of long, narrow cells
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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 epitheliumtransitional epithelium
This specialized tissue is capable of expanding and returning to its original form
Examples of epithelial tissue are: Urinary bladder > Uterus
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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
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GlandsGlands – 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:
1. Exocrine Glands2. Endocrine Glands
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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
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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
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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
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Soft Connective Tissue Loosely held together with a semi-liquid material
between cells Adipose (Fat) TissueAdipose (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) TissueAreolar (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
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Liquid Connective Tissue Suspended in a fluid environment
Ex:
Blood
Lymph (fluid that circulates the lymphatic system)
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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
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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
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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.
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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
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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:
1. Skeletal2. Cardiac3. Smooth
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Skeletal Muscle Works with tendons &
bones to move the body
Known as “voluntary” muscle
Moves or contracts by conscious thought
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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
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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”
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Nervous Tissue
Makes up the entire “communication” system of the brain, nerves and spinal cord
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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
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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
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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
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- 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
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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
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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
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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: PapillomaPapilloma: grows in epithelium, such as a wart OsteomaOsteoma: originates in the bones MyomaMyoma: originates in muscle tissue; common mostly in
involuntary muscle, particularly in the uterus (Fibroid Tumors)
AngiomaAngioma: composed of small blood vessels; more commonly known as a birthmark
NevusNevus: skin tumors; better known as moles which are ordinarily harmless, but can become malignant
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Papilloma – a common wart
Mastoid Osteoma – tumor of the bone behind the ear
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Fibroid Tumor (Myoma)
Birthmark (Angioma)
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Mole (Nevus)
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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
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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
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Sarcoma
Cancer of the connective tissue Can be found anywhere in the body Usually spreads by the bloodstream
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Gastric LymphomaA 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
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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
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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
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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