BIO Ch 4- The Tissue Level of Organization.docx - 1...

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Biology: Human Anatomy and Physiology
CH. 4: THE TISSUE LEVEL OF ORGANIZATION
1.
Define the term tissue, and classify the tissues of the body into four major types.
A.
tissue
● A tissue is a group of cells that usually have a common origin and function, and
they work together to carry out a specific activity.
B.
histology
● The science that deals with the study of tissues
I.
epithelial tissue
● covers body surfaces and lines hollow organs, body cavities, and ducts; it
also forms glands. This tissue allows the body to interact with both its
internal and external environments.
● Most common type of tissue
II.
connective tissue
● protects and supports the body and its organs. Various types of
connective tissues bind organs together, store energy reserves as fat, and
help provide the body with immunity to disease-causing organisms.
III.
muscular tissue
● is composed of cells specialized for contraction and generation of force.
In the process, muscular tissue generates heat that warms the body.
IV.
nervous tissue
● detects changes in a variety of conditions inside and outside the body and
responds by generating electrical signals called nerve action potentials
(nerve impulses) that activate muscular contractions and glandular
secretions.
2. What are some key differences in function among the four tissue types?
● Epithelial tissue covers the body, lines various structures, and forms glands.
● Connective tissue protects, supports, binds organs together, stores energy, and helps
provide immunity.
● Muscular tissue contracts and generates force and heat.
● Nervous tissue detects changes in the environment and generates nerve impulses that
activate muscular contraction and glandular secretion
3. What is a biopsy?
● A biopsy is the surgical removal of a sample via a needle or syringe of living tissue for
microscopic examination.
● This is used to help diagnose many disorder, especially cancer.
4.
Describe the structure and functions of the five principal types of cell junctions.
A.
cell junction

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● Cell junctions Are contact points between the plasma membranes of the tissue
cells. There are five different types of cell junctions:
1. tight junction
➔ Web like strands of transmembrane proteins. they fused together
the outside surfaces of the adjacent plasma membrane
➔ they allow the passage of substances between cells and prevent
the contents of the organs from leaking into the blood or
surrounding tissue.
➔ tissues that line the stomach, intestines, urinary bladder.
2. adherens junction
➔ These contain plaque, which is a dense layer of protein on the
inside of the plasma membrane, this attaches both to the
membrane protein and to the microfilaments of the cytoskeleton.
➔ Cadherins join the cells
➔ These Junctions are known for zones called “adhesion belts”
because they encircle the cell.