Tissue: The Living Fabric Chapter 4

Differentiate between exocrine and endocrine glands, and between multicellular and unicellular glands.

1. Endocrine glands are ductless glands that secrete hormones by exocytosis directly into the blood or lymph 2. Exocrine glands have ducts and secrete their product onto a surface or into body cavities a. Exocrine glands can be multicellular or unicellular b. Exocrine secretions in humans may be merocrine, which are products released through exocytosis, or holocrine, which are synthesized products released when the cell ruptures

4.1 List the steps involved in preparing animal tissue for microscopic viewing

1. Fixed (preserved) 2. Cut into sections (slices) thin enough to transmit light or electrons 3. Stain to enhance contrast

Describe the types of connective tissue found in the body, and indicate they characteristic functions.

1. Mesenchyme forms during the early weeks of embryonic development from the mesoderm layer and eventually differentiates into all other connective tissues 2. Loose connective tissue is one of the two subclasses of connective tissue proper a. Areolar connective tissue serves to bind body parts together while allowing them to move freely over one another, wraps small blood vessels and nerves, surrounds glands, and forms the subcutaneous tissue b. Adipose (fat) tissue is a richly vascularized tissue that functions in nutrient storage, protection, and insulation c. Reticular connective tissue forms the internal framework of the lymph nodes, the spleen, and the bone marrow 3. Dense connective tissue is one of the two subclasses of connective tissue proper a. Dense regular connective tissue contains closely packed bundles of collagen fibers running In the same direction and makes up tendons and ligaments b. Dense irregular connective tissue contains thick bundles of collagen fibers arranged in an irregular fashion, and is found in the dermis

Name, classify, and describe the various types of epithelia, and indicate their chief function(s) and location(s).

1. Simple Squamous- laterally flattened, sparse cytoplasm, disc shaped nuclei; allows materials to pass by diffusion and filtration in sites where protection isn't important; In kidney, glomeruli, air sacs in lungs, lining of heart, blood vessels, lymphatic vessels, serosae 2. Simple Cuboidal- Single layer of cube like cells, large spherical central nuclei; secretion and absorption; kidney tubules, ducts and secretory portions of small glands, ovary surface 3. Simple Columnar-Single layer, tall cells, round to oval nuclei, some have cilia, may contain mucus-secreting unicellular glands; absorption, secretion of mucus and enzymes, ciliated type propels mucus; Non Ciliated-lines digestive tract, gallbladder, and excretory ducts; Ciliated- lines small bronchi, uterine tubes, some regions of uterus 4. Pseudostratified Columnar- Single layer of cells of differing heights, some not reaching free surface; nuclei seen at different levels; may contain mucus secreting cells and bear cilia; secrete substances, particularly mucus; propulsion of mucus by ciliary action; Nonciliated-male's sperm carrying ducts and ducts of large glands; Ciliated-lines trachea and most of upper respiratory tract 5. Stratified Squamous-think membrane, composed of cell layers, basal cells are cuboidal or columnar and metabolically active, surface cells are flattened (squamous). In keratinized type, surface cells are full of keratin and dead. Basal cells are active in mitosis and produce the cells of the more superficial layers. Protects underlying tissues in areas subjected to abrasion. Nonkeratinzed-forms in most linings of esophagus, mouth, vagina. Keratinized-forms the epidermis of skin 6. Transitional-Resembles both stratified squamous and stratified cuboidal. Basal cells cuboidal and columnar. Surface cells dome shaped or squamous like, depending on degree of organ stretch; Stretched readily, permits stored urine to distend urinary organ; Lines ureters, bladder and part of urethra

4.4 Compare and contrast the structures and body locations of the three types of muscle tissue.

1. Skeletal muscle attaches to the skeleton and produces voluntary body movement 2. Cardiac muscle is responsible for the involuntary movement of the heart 3. Smooth muscle is found in the walls of the hollow organs

3. Match the epithelial types named in column B with the appropriate description(s) in column A. Column A _1. Lines most of the digestive tract _2. Lines the esophagus _3. Lines much of the respiratory tract _4. Forms the walls of the air sacs of the lungs _5. Found in urinary tract organs _6. Endothelium and mesothelium Column B a. pseudostratified ciliated columnar b. simple columnar c. simple cuboidal d. simple squamous e. stratified columnar f. stratified squamous g. transitional

1. b 2. f 3. a 4. d 5. g 6. d

4.3 Indicate common characteristics of connective tissue, and list and describe its structural elements.

A. Common Characteristics of Connective tissue 1. Common origin: all connective tissue arises from an embryonic tissue called mesenchyme 2. Degrees of vascularity: Connective tissue ranges from avascular to highly vascularized 3. Extracellular matrix: Because of its matrix, connective tissue can bear weight, withstand great tension, and endure abuses, such as physical trauma and abrasion, that no other tissue can tolerate. B. Structural Elements 1. Ground substance: is the unstructured material that fills the space between the cells and contains the fibers 2. Connective Tissue Fibers: the fibers of connective tissue are proteins that provide support. A. Connective Tissue Cells: Collagen fibers are extremely strong and provide high tensile strength to the connective tissue b. Elastic fibers contain elastin, which allows them to be stretched and to recoil c. Reticular fibers are fine, collagenous fibers that form networks 3. Each major class of connective tissue has a fundamental cell type that exists in immature and mature forms

4.5 Indicate the general characteristics of nervous tissue

A. Nervous tissue is the main component of the nervous system, which regulates and controls body functions B. Nervous tissue is composed of two types of cells 1. Neurons are specialized cells that generate and conduct electrical impulses 2. Supporting cells are nonconductive cells that support, insulate, and protect the neurons

4.7 Outline the process of tissue repair involved in normal healing of a superficial wound.

A. Tissue repair occurs in two ways: regeneration and fibrosis B. Three steps are involved in the tissue repair process 1. Inflammation prepares the area for the repair process 2. Organization restores the blood supply 3. Regeneration and fibrosis effect permanent repair C. The generative capacity of tissues varies widely among the tissue types

21. In what ways are adipose tissue and bone similar? How are they different?

Adipose and bone tissue are similar in that both tissues are connective tissues with a rich blood supply and are used for nutrient storage. They are different in their relative amounts of extracellular matrix and location of nutrient storage. Bone has ample extracellular matrix, and this is the location of nutrient storage. Adipose tissue has little extracellular matrix, and stores nutrients within the cells.

10. Which connective tissue has a soft web-like matrix capable of serving as a fluid reservoir?

Areolar connective tissue.

8. What are the functions of connective tissue?

Binding/supporting, protecting, insulating, and storing reserve fuel.

11. Provide examples from the body that illustrate four of the major functions of connective tissue.

Binding—areolar; support—cartilage; protection—bone; insulation—adipose; and transportation—blood.

13. You are looking at muscle tissue through the microscope and you see striped branching cells that connect with one another. What type of muscle are you viewing?

Cardiac muscle have striations and are branching cells.

9. What are the three types of fibers found in connective tissues?

Collagen fibers, elastic fibers, and reticular fibers.

4.6 Describe the structure and function of cutaneous, mucous, and serous membranes.

Cutaneous membrane (skin) covers the body surface Mucous membranes line body cavities that are open to the exterior Serous membranes line body cavities that are closed to the exterior

11. What type of connective tissue is damaged when you cut your index finger tendon?

Dense regular connective tissue.

20. Indicate which primary tissue classes derive from each embryonic germ layer

Ectoderm—epithelium and nervous Mesoderm—connective, muscle, and epithelium Endoderm—epithelium

3. Epithelial tissue is the only tissue type that has polarity, that is, an apical and a basal surface. Why is this important?

Epithelial tissue lines body cavities and covers the body's external surface; thus polarity with one free (apical) surface is a requirement.

12. Name the primary cell type in connective tissue proper; in cartilage; in bone.

Fibroblast (connective tissue proper); chondroblast(in cartilage); osteoblast(in bone).

4.2 List several structural and functional characteristics of epithelial tissue

Functional: protection, absorption, filtration, excretion, secretion, and sensory reception Structural: apical-basal polarity, microvilli and cilia, basal lamina, fit closely together, six sides, simple and stratified, squamous and cuboidal and columnar, nucleus is shaped along with the cell

13. Name the two major components of matrix and, if applicable, subclasses of each component.

Ground substance—interstitial fluid, proteoglycans, and glycosaminoglycans; fibers—collagen, elastic, reticular.

4. Which gland type, merocrine or holocrine, would you expect to have the highest rate of cell division? Why?

Holocrine cells because of how they excrete their products - they accumulate product until they rupture, thus resulting in a need for a higher reproduction rate.

19. What are the three main steps of tissue repair?

Inflammation, organization, and regeneration and fibrosis.

10. Explain the functional classification of each multicellular exocrine glands and supply an example for each class.

Merocrine glands (sweat glands) secrete their products by exocytosis; holocrine glands (oil glands) release their products by lysis of the entire cell; apocrine (not believed to be present in humans) release their products by pinching off parts of the cell contents.

Describe how multicellular exocrine glands are classified structurally and functionally

Multicellular exocrine glands are classified according to duct structure as simple or compound, and according to the structure of their secretory parts as tubular, alveolar, or tubuloalveolar Multicellular exocrine glands of humans are classified functionally as merocrine or holocrine

17. Differentiate between the roles of neurons and the supporting cells of nervous tissue.

Neurons are highly specialized cells that generate and conduct nerve impulses, whereas the supporting cells (neuroglial) are nonconducting cells that support, insulate, and protect the neurons.

8. Name 4 important functions of epithelial tissue and provide at least 1 example of a tissue that exemplifies each function.

Protection—stratified squamous; absorption—simple columnar; filtration—simple squamous; secretion—simple cuboidal.

6. Some epithelia are pseudo-stratified. What does this mean?

Pseudo-stratified epithelia appear to be stratified because their cells' nuclei lie at different distances from the basement membrane. However, all cells rest on the basement membrane.

5. Stratified epithelia are "built" for protection or to resist abrasion. What are the simple epithelia better at?

Simple epithelia are "built" for efficient absorption and filtration.

14. Which muscle is voluntary? Which is injured when you pull a muscle while exercising?

Skeletal muscles is voluntary and is the muscle tissue injured when you "pull a muscle" while exercising.

9. Describe the criteria used to classify covering and lining epithelia.

The covering and lining epithelia are classified on the basis of the shape of the cells and the number of cell layers present. The three common shapes are squamous, cuboidal, and columnar. The classes in terms of cell number are: simple (single layer) or stratified (multiple layers). In some cases, such as with endothelium, it is important to indicate their special location in the body.

16. What is the function of macrophages?

The macrophage system is involved in overall body defenses. Its cells are phagocytic and act in the immune response.

14. Matrix is extracellular. How does the matrix get to its characteristic position?

The matrix gets to its position due to secretion of its components by the undifferentiated (blast) cells located throughout the matrix.

19. Describe the process of tissue repair, making sure you indicate factors that influence this process

Tissue repair begins during the inflammatory response with organization, during which the blood clot is replaced by granulation tissue. If the wound is small and the damaged tissue is actively mitotic, the tissue will regenerate and cover the fibrous tissue forced to bridge the gap. When a wound is extensive or the damaged tissue amitotic, it is repaired only by using fibrous connective (scar) tissue.

2. What types of stains are used to stain tissues to be viewed with an electron microscope?

Tissue sections are stained with heavy metal salts in order to be viewed by an electron microscope.

1. What is the purpose of fixing tissue for microscopic viewing?

Tissue structure can be viewed through a microscope once its fixed (preserved), and then cut into sections (slices) thin enough to transmit light or electrons, finally it must be stained to enhance contrast.

7. Define tissue

Tissues are groups of closely associated cells that are similar in structure and perform a common function.

7. Where is transitional epithelium found and what is its importance at those sites?

Transitional epithelium is found in the urinary bladder and other hollow urinary organs. The ability of this epithelium to thin allows the urinary organs to handle (story or transport) a larger urine volume when necessary.

15. How does the extended length of a neuron's processes aid its function in the body?

With extended processes, a neuron can conduct electrical signals a great distance within the body.

muscle

______The tissue immediately responsible for body movement

nervous tissue

______The tissue that enables us to be aware of the external environment and to react to it

epithelium

______The tissue that lines body cavities and covers surfaces

1. connective tissue

______Tissue type composed largely of nonliving extracellular matrix, important in protection and support

15. Name the specific connective tissue type found in the following body locations: (a) forming the soft packing around organs (b) supporting the ear pinna (c) forming "stretchy" ligaments (d) first connective tissue in the embryo (e) forming the intervertebral discs (f) covering the ends of bones at joint surfaces (g) main component of subcutaneous tissue

a. areolar (p. 126) b. elastic cartilage (p. 133) c. elastic connective tissue (p. 131) d. mesenchyme (p. 126) e. fibrocartilage (p. 133) f. hyaline cartilage (p. 131) g. areolar connective tissue

4. The gland type that secretes products such as milk, saliva, bile, or sweat through a duct is a. an endocrine gland b. an exocrine gland

b. an exocrine gland

6. Scar tissue is variety of

b. connective tissue

5. The membrane which lines body cavities that open to the exterior is a(n)

c. mucous membrane

2. An epithelium that has several layers, with an apical layer of flattened cells, is called

c. stratified e. squamous

Define gland

consists of one or more cells that make and secrete a particular product.

20. Why does a deep injury to the skin result in abundant scar tissue?

more severe injuries damage and destroy more tissue, requiring greater replacement with scar tissue.

16. What type of membrane consists of epithelium and connective tissue, and lines body cavities open to the exterior?

mucous membrane

12. It has been observed that aging cartilage tends to calcify or ossify and its cells die. What survival needs are not being met in these cells and why is this so?

oxygen and nutrient needs because the calcified cartilage matrix is too hard to allow them to reach the cells by diffusion

17. What type of membrane lines the thoracic walls and covers the lungs, and what is it called?

serous membrane. when it covers the lungs, it's called the visceral pleura.

18. The two layers of serous membranes are held together by serous fluid, which is largely water. Which of the properties of water (chapter 2) makes these layers "stick" together?

water's high surface tension (due to hydrogen bonds) makes the layers of serous membrane stick together.