Ch 4 Flashcards
Tissue
~Tissues are a group of cells with a common embryonic origin that function together to carry out specialized activities. ~They include various types, ranging from hard (bone) to semisolid (fat) to liquid (blood).
Histology
is the study of the microscopic anatomy of cells and tissues – it is a branch of pathology
Intracellular Junctions
~Tissues are formed by grouping cells together using a variety of Intercellular Junctions . ~Intracellular Junctions connect adjacent cells mechanically at the cell membranes or through cytoskeletal elements within and between cells.
Tight Junctions
are found where a leakproof seal is needed between cells. ~They keep materials from leaking out of organs like the stomach and bladder.
Adherens Junctions
make an adhesion belt (like the belt on your pants) that keeps tissues from separating as they stretch and contract.
Adherens Junctions Cadherin
is a glycoprotein that forms the belt-like “plaque”.
Desmosomes
act as “spot welds”. They also use cadherin glycoprotein (plus intermediate filaments) to hook into the cytoplasm.
Hemidesmosomes
are half-welds that join cells to the basement membrane.
Gap Junctions
are pores (connexons) that allow small substances like ions to pass between cells. If one of the cells gets sick or dies, these seal like a hatch to prevent damage to other cells.
4 Basic Tissues
~Of all the cells in the body, they combine to make only 4 basic tissue types:
~Epithelial tissues
~Connective tissues
~Muscular tissues
~Nervous tissues
Epithelial tissues
cover body surfaces and form glands and line hollow organs, body cavities, and ducts.
Connective tissues (C.T.)
protect, support, and bind organs. ~Fat is a type of C.T. that stores energy. ~Red blood cells, white blood cells, and platelets are all C.T.
Muscular tissues
generate the physical force needed to make body structures move. They also generate heat used by the body.
Nervous tissues
detect changes in the body and respond by generating nerve impulses.
4 Basic Tissues
Tissues of the body develop from three primary germ layers: Endoderm, Mesoderm, and Ectoderm
~Epithelial tissues from all three germ layers
~C.T. and muscle are derived from mesoderm.
~Nervous tissue develops from ectoderm.
Epithelium
~Epithelium is used to line surfaces and form protective barriers. Epithelium is also good at secreting things like mucous, hormones, and other substances .
~All epithelia have a free apical surface and an attached basal surface.
Epithelium
~The basal layer of the epithelium secretes a basal lamina; the underlying C.T. secretes a reticular lamina.
~Together the basal lamina and the reticular lamina form a non-cellular basement membrane on which the epithelium sits.
Epithelium
Epithelia are named according to the shape of their cells, and the thickness or arrangement of their layers (of cells).
~simple
~pseudostratified
~stratified
Epithelium
Naming epithelia according to shape
~squamous: Flat, wide “paving stone cells”
~Cuboidal: cells as tall as they are wide
~Columnar: cells taller than they are wide
Simple Squamous Epithelium
is composed of a single layer of flat cells found: ~In the air sacs of lungs ~In the lining of blood vessels, the heart, and lymphatic vessels ~In all capillaries, including those of the kidney. ~As the major part of a serous membrane
Simple Cuboidal Epithelium
~is composed of a single layer of cube shaped cells. ~It is often found lining the tubules of the kidneys and many other glands.
Simple Columnar Epithelium
forms a single layer of column-like cells, ± cilia, ± microvilli, ± mucous (goblet cells). ~Goblet cells are simple columnar cells that have differentiated to acquire the ability to secrete mucous.
Pseudostratified Columnar Epithelium
~ appears to have layers, due to nuclei which are at various depths. In reality, all cells are attached to the basement membrane in a single layer, but some do not extend to the apical surface. ~Ciliated tissue has goblet cells that secrete mucous.
Stratified Squamous Epithelium
~has an apical surface that is made up of squamous (flat) cells. ~The other layers have different shapes, but the name is based on the apical layer. ~The many layers are ideal for protection against strong friction forces.
Stratified Cuboidal Epithelium
~has an apical surface made up of two or more layers of cube-shaped cells. ~Locations include the sweat glands and part of the ♂ urethra
Stratified Columnar Epithelium
is very rare, and for our purposes, hardly worth mentioning.
Transitional Epithelium
~change shape depending on the state of stretch in the tissue. ~The apical “dome cells” of the top layer (seen here in relaxation) are an identifiable feature and signify an empty bladder . ~In a full bladder, the cells are flattened.
Epithelium
~Although epithelia are found throughout the body, certain ones are associated with specific body locations. ~Stratified squamous epithelium is a prominent feature of the outer layers of the skin.
Epithelium
~Simple squamous makes up epithelial membranes and lines the blood vessels. ~Columnar is common in the digestive tract. ~Pseudostratified ciliated columnar is characteristic of the upper respiratory tract. ~Transitional is found in the bladder. ~Cuboidal lines ducts and sweat glands.
Covering and Lining Epithelium Endothelium
is a specialized simple squamous epithelium that lines the entire circulatory system from the heart to the smallest capillary – it is extremely important in reducing turbulence of flow of blood
Covering and Lining Epithelium Mesothelium
Mesothelium is found in serous membranes such as the pericardium, pleura, and peritoneum. Unlike other epithelial tissue, both are derived from embryonic mesoderm (the middle layer of the 3 primary germ layers of the embryo).
Connective Tissue
~are the most abundant and widely distributed tissues in the body – they are also the most heterogeneous of the tissue groups. ~They perform numerous functions: *Bind tissues together *Support and strengthen tissue *Protect and insulate internal organs *Compartmentalize and transport *Energy reserves and immune responses
Connective Tissues
~Collagen is the main protein of C.T. and the most abundant protein in the body, making up about 25% of total protein content. ~Connective tissue is usually highly vascular and supplied with many nerves. ~The exception is cartilage and tendon - both have little or no blood supply and no nerves.
Connective Tissues
~Although they are a varied group, all C.T. share a common “theme”: *Sparse cells *Surrounded by an extracellular matrix ~The extracellular matrix is a non-cellular material located between and around the cells. *It consists of protein fibers and ground substance (the ground substance may be fluid, semifluid, gelatinous, or calcified.)
Cells of Connective Tissues
~Common C.T. cells ~Fibroblasts are the most numerous cell of connective tissues. These cells secrete protein fibers (collagen, elastin, & reticular fibers) and a “ground substance” which varies from one C.T. to another.
Cells of Connective Tissues
Of the other common C.T. cells: *Chondrocytes make the various cartilaginous C.T. *Adipocytes store triglycerides. *Osteocytes make bone. *White blood cells are part of the blood.
Connective Tissue
~There are 5 types of white blood cells (WBCs): *Macrophages are the “big eaters” that swallow and destroy invaders or debris. They can be fixed or wandering. *Neutrophils are also macrophages (“small eaters”) that are numerous in the blood. *Mast cells and Eosinophils play an important role in inflammation. *Lymphocytes secrete antibody proteins and attack invaders.
Connective Tissues
~C.T. cells secrete 3 common fibers: *Collagen fibers *Elastin fibers *Reticular fibers
Connective Tissue Classification
~Embryonic connective tissue *Mesenchyme *Mucous connective tissue ~Mature connective tissue *Loose connective tissue *Dense connective tissue *Cartilage *Bone *Liquid
Embryonic Connective Tissues
~There are 2 Embryonic Connective Tissues: *Mesenchyme gives rise to all other connective tissues. *Mucous C.T. (Wharton’s Jelly) is a gelatinous substance within the umbilical cord and is a rich source of stem cells.
Mature Connective Tissues- Loose Connective Tissues Areolar Connective Tissue
is the most widely distributed in the body. It contains several types of cells and all three fiber types. ~It is used to attach skin and underlying tissues, and as a packing between glands, muscles, and nerves.
Mature Connective Tissues- Loose Connective Tissues Adipose tissue
is located in the subcutaneous layer deep to the skin and around organs and joints. It reduces heat loss and serves as padding and as an energy source.
Mature Connective Tissues- Loose Connective Tissues Reticular connective tissue
is a network of interlacing reticular fibers and cells. ~It forms a scaffolding used by cells of lymphoid tissues such as the spleen and lymph nodes.
Mature Connective Tissues- Dense Connective Tissues Dense Irregular Connective Tissue
consists predominantly of fibroblasts and collagen fibers randomly arranged. ~It provides strength when forces are pulling from many different directions.
Mature Connective Tissues- Dense Connective Tissues Dense Regular Connective Tissue
comprise tendons, ligaments, and other strong attachments where the need for strength along one axis is mandatory (a muscle pulling on a bone).
Mature Connective Tissues- Dense Connective Tissues Elastic Connective Tissue
consists predominantly of fibroblasts and freely branching elastic fibers. ~It allows stretching of certain tissues like the elastic arteries (the aorta).
Mature Connective Tissues Cartilage
is a tissue with poor blood supply that grows slowly. When injured or inflamed, repair is slow.
Mature Connective Tissues Hyaline cartilage
is the most abundant type of cartilage; it covers the ends of long bones and parts of the ribs, nose, trachea, bronchi, and larynx. ~It provides a smooth surface for joint movement.
Mature Connective Tissues Fibrocartilage
with its thick bundles of collagen fibers, is a very strong, tough cartilage. ~Fibrocartilage discs in the intervertebral spaces and the knee joints support the huge loads up and down the long axis of the body.
Mature Connective Tissues Elastic Cartilage
consists of chondrocytes located in a threadlike network of elastic fibers. ~It makes up the malleable part of the external ear and the epiglottis.
Mature Connective Tissues Bone
is a connective tissue with a calcified intracellular matrix. In the right circumstances, the chondrocytes of cartilage are capable of turning into the osteocytes that make up bone tissue.
Mature Connective Tissues Blood and lymph Bone
is a connective tissue with a calcified intracellular matrix. In the right circumstances, the chondrocytes of cartilage are capable of turning into the osteocytes that make up bone tissue.
Muscle and Nerve Tissues
~Muscles and nerve tissues are the last of the 4 basic tissue types. Neurons and muscle fibers are considered excitable cells because they exhibit electrical excitability, the ability to respond to certain stimuli by producing electrical signals such as action potentials. ~Action potentials can propagate (travel) along the plasma membrane of a neuron or muscle fiber due to the presence of specific voltage-gated ion channels.
Epithelial Membranes
Combining two tissues creates an organ. However, most of the organs and all of the organs systems studied this year contain all 4 basic types of tissues. ~Epithelial membranes are the simplest organs in the body, constructed of only epithelium and a little bit of connective tissue.
Epithelial Membranes
Epithelial membranes = epithelium + connective tissue ~Mucous membranes ~Serous membranes ~Cutaneous membrane = skin *Skin is not a simple organ.
Epithelial Membranes
~Mucous membranes line “interior” body surfaces open to the outside: *Digestive tract *Respiratory tract *Reproductive tract ~Serous membranes line some internal surfaces: *Parietal layer next to body wall *Serous fluid between layers *Visceral layer next to organ
Synovial membranes
enclose certain joints and are made of connective tissue only.
Glands
Epithelial glands are another example of simple organs *Glands that secrete their contents directly into the blood are called endocrine glands. *Glands that secrete their contents into a lumen or duct are called exocrine glands. We will look at some common types of exocrine glands
Exocrine Glands
~Exocrine glands secrete substances through ducts to the surface of the skin or into the lumen of a hollow organ. *Secretions of the exocrine gland include mucus, sweat, oil, earwax, saliva, and digestive enzymes. ~Examples of exocrine glands are sudoriferous (sweat) glands.
Exocrine Glands
The two criteria for categorizing multicellular glands according to structure: ~Whether the ducts are branched or unbranched… *In a simple gland the duct does not branch. *In a compound gland the duct branches. ~… and the shape of the secretory portion of the gland *Tubular glands have tubular secretory parts. *Acinar glands have rounded secretory parts. *Tubuloacinar glands have features of both.
Exocrine Glands
The criteria for categorizing multicellular glands according to function is based on the manner in which the gland secretes its product from inside the cell to the outside environment
. *Merocrine
*Apocrine
*Holocrine
Exocrine Glands Merocrine
Merocrine secretion is the most common manner of secretion. ~The gland releases its product by exocytosis and no part of the gland is lost or damaged
Exocrine Glands
Apocrine Glands
“bud” their secretions off through the plasma membrane, producing membrane-bound vesicles in the lumen of the gland. ~The end of the cell breaks off by “decapitation”, leaving a milky, viscous odorless fluid. ~This type of sweat only develops a strong odor when it comes into contact with bacteria on the skin surface.
Exocrine Glands
Holocrine Secretions
are produced by rupture of the plasma membrane, releasing the entire cellular contents into the lumen and killing the cell (cells are replaced by rapid division of stem cells.) ~The sebaceous gland is an example of a holocrine gland, because its secretion (sebum) is released with remnants of dead cells.
Tissue Repair
~ A convenient way to refer to certain cells when discussing a tissue is Parenchyma or Stroma. *The parenchymal cells of an organ consist of that tissue which conducts the specific function of the organ. Cells of the stroma are everything else—connective tissue, blood vessels, nerves. ~For example: The parenchyma of the heart is cardiac muscle cells. The nerves, intrinsic blood vessels, and connective tissue of the heart comprise the stroma.
Tissue Repair
~Parenchyma is interesting. Because organ-specific function usually centers on parenchymal cells (“how’s your heart working?”), histological and physiological descriptions of the tissues of an organ often emphasize parenchyma. ~Unfortunately, stroma is commonly ignored as just boring background tissue. No organ, however, can function without the mechanical and nutritional support provided by the stroma.
Tissue Repair
~When tissue damage is extensive, return to homeostasis depends on active repair of both parenchymal cells and stroma. *Fibroblasts divide rapidly. *New collagen fibers are manufactured. *New blood capillaries supply materials for healing. ~All of these processes create an actively growing connective tissue called granulation tissue
Aging and Tissues
~Tissue heals faster in young adults. ~Surgery of a fetus normally leaves no scars. ~Young tissues have a better nutritional state, blood supply, and higher metabolic rate. ~Extracellular components also change with age. ~Changes in the body’s use of glucose, collagen, and elastic fibers contribute to the aging process.
Which of the cell junctions would prevent leaking from the transitional epithelium lining the urinary bladder?
Tight Junctions
Which of the following is not a type of connective tissue?
a. areolar tissue
b. cartilage
c. bone tissue
d. blood
e. glandular tissue
e. glandular tissue
Which property of epithelium enables it to form coverings and linings of the body?
a. epithelium is avascular
b. epithelium can regenerate rapidly
c. epithelium is attached at the basement membrane
d. epithelial cells are closely packed and the cells are tightly adhered to one another
d. epithelial cells are closely packed and the cells are tightly adhered to one another
Most neurons are composed of a cell body and two processes called axons and dendrites.
True
False
True
Most epithelial and connective tissues in the body will repair if they receive proper nutrition and have a blood source.
True
False
True
In aging tissue, glucose-protein combinations form abnormal cross links with proteins.
True
False
True
Which of these is avascular?
a. skeletal muscle
b. neuroglia
c. bone
d. cartilage
d. cartilage
Both muscle and nervous tissue can produce electrical signals because they have special voltage gated ion channels.
True
False
True
Which type of muscle is not controlled by the autonomic nervous system?
a. smooth
b. skeletal
c. cardiac
b. skeletal
The visceral pleura described in chapter 1 would consist of
a. lamina propria and simple cuboidal epithelium
b. areolar connective tissue and mesothelium
c. lamina propria and mesothelium
d. simple squamous epithelium
b. areolar connective tissue and mesothelium
The four types of tissues are ________, ________, ________, and ________.
Epithelial, Connective, Muscle, Nerve
Epithelial tissue tends to be classified according to two criteria: ________ and ________.
Arrangement of cells in layers
Cell shape
T or F: Epithelial tissue cells have an apical surface at the top and are attached to a basement membrane at the bottom.
True
T or F: Connective tissue fibers that are arranged in bundles and lend strength and flexibility to a tissue are collagen fibers.
True
Which of the following muscular tissues can be voluntarily controlled? (1) cardiac, (2), smooth, (3) skeletal.
a. 1, 2, and 3
b. 2
c. 1
d. 1 and 3
e. 3
e. 3
Which of the following tissues is avascular?
a. cardiac muscle
b. stratified squamous epithelial
c. compact bone
d. skeletal muscle
e. adipose
e. adipose
If the lining of an organ produces and releases mucus, which of the following cells would likely be found in the tissue lining the organ?
a. goblet cells
b. mast cells
c. macrophages
d. osteoblasts
e. fibroblasts
a. goblet cells
Why does damaged cartilage heal slowly?
a. Damaged cartilage undergoes fibrosis, which interferes with the movement of materials needed for repair.
b. Cartilage does not contain fibroblasts, which are needed to produce the fibers in cartilage tissue.
c. Cartilage is avascular, so materials needed for repair must diffuse from surrounding tissue.
d. Chondrocytes cannot be replaced once they are damaged.
e. Chondrocytes undergo mitosis slowly, which delays healing.
c. Cartilage is avascular, so materials needed for repair must diffuse from surrounding tissue.
Which of the following is true concerning serous membranes?
a. A serous membrane lines a body part that opens directly to the body’s exterior.
b. The parietal portion of a serous membrane attaches to the organ.
c. The visceral portion of a serous membrane attaches to a body cavity wall.
d. The serous membrane covering the heart is known as the peritoneum.
e. The serous membrane covering the lungs is known as the pleura.
e. The serous membrane covering the lungs is known as the pleura
The type of exocrine gland that forms its secretory product and simply releases it from the cell by exocytosis is the
a. apocrine gland
b. merocrine gland
c. holocrine gland
d. endocrine gland
e. tubular gland.
b. merocrine gland
Tissue changes that occur with aging can be due to (1) cross‐links forming between glucose and proteins, (2) a decrease in the amount of collagen fibers, (3) a decreased blood supply, (4) improper nutrition, (5) a higher cellular metabolic rate.
a. 1, 2, 3, 4, and 5
b. 1, 2, 3, and 4
c. 1 and 4
d. 1, 3, and 4
e. 1, 2, and 3
d. 1, 3, and 4
What type of cell junction would be required for cells to communicate with one another?
a. adherens junction
b. desmosome
c. gap junction
d. tight junction
e. hemidesmosome
c. gap junction
Match the following epithelial tissues to their descriptions:
___ a. contains a single layer of flat cells; found in the body where filtration (kidney) or diffusion (lungs) are priority processes
___ b. found in the superficial part of skin; provides protection from heat, microbes, and chemicals
___ c. contains cube‐shaped cells functioning in secretion and absorption
___ d. lines the lower respiratory tract and uterine tubes; wavelike motion of cilia propels materials through the lumen
___ e. contains cells with microvilli and goblet cells; found in linings of the digestive, reproductive, and urinary tracts
___ f. found in the urinary bladder; contains cells that can change shape (stretch or relax)
___ g. contains cells that are all attached to the basement membrane, although some do not reach the surface; those cells that do extend to the surface secrete mucus or contain cilia
___ h. a fairly rare type of epithelium that has a mainly protective function
- pseudostratified ciliated columnar epithelium
- ciliated simple columnar epithelium
- transitional epithelium
- simple squamous epithelium
- simple cuboidal epithelium
- nonciliated simple columnar epithelium
- stratified cuboidal epithelium
- keratinized stratified squamous epithelium
4 a. contains a single layer of flat cells; found in the body where filtration (kidney) or diffusion (lungs) are priority processes
8 b. found in the superficial part of skin; provides protection from heat, microbes, and chemicals
5 c. contains cube‐shaped cells functioning in secretion and absorption
2 d. lines the lower respiratory tract and uterine tubes; wavelike motion of cilia propels materials through the lumen
6 e. contains cells with microvilli and goblet cells; found in linings of the digestive, reproductive, and urinary tracts
3 f. found in the urinary bladder; contains cells that can change shape (stretch or relax)
1 g. contains cells that are all attached to the basement membrane, although some do not reach the surface; those cells that do extend to the surface secrete mucus or contain cilia
7 h. a fairly rare type of epithelium that has a mainly protective function
For each of the following items, indicate the tissue type with which they are associated. Use E for epithelial tissues, C for connective tissues, M for muscle tissues, and N for nervous tissue.
___ a. bind, support
___ b. contains elongated cells that generate force
___ c. neuroglia
___ d. avascular
___ e. may contain fibroblasts
___ f. tightly packed cells
___ g. intercalated discs
___ h. goblet cells
___ i. contain extracellular matrix
___ j. striated
___ k. generate action potentials
___ l. cilia
___ m. ground substance
___ n. apical surface
___ o. excitable
_c_ a. bind, support
_m_ b. contains elongated cells that generate force
_N_ c. neuroglia
_E_ d. avascular
_C_ e. may contain fibroblasts
_E_ f. tightly packed cells
_M_ g. intercalated discs
_E_ h. goblet cells
_C_ i. contain extracellular matrix
_M_ j. striated
_N_ k. generate action potentials
_E_ l. cilia
_C_ m. ground substance
_E_ n. apical surface
N,M o. excitable
Match the following connective tissues to their descriptions:
___ a. the tissue from which all other connective tissues eventually arise
___ b. connective tissue with a clear, liquid matrix that flows in lymphatic vessels
___ c. connective tissue consisting of several kinds of cells, containing all three fiber types randomly arranged, and found in the subcutaneous layer deep to the skin
___ d. a loose connective tissue specialized for triglyceride storage
___ e. tissue that contains reticular fibers and reticular cells and forms the stroma of certain organs such as the spleen
___ f. tissue with irregularly arranged collagen fibers found in the dermis of the skin
___ g. tissue found in the lungs that is strong and can recoil back to its original shape after being stretched
___ h. tissue that affords flexibility at joints and reduces joint friction
___ i. tissue that provides strength and rigidity and is the strongest of the three types of cartilage
___ j. bundles of collagen arranged in parallel patterns; compose tendons and ligaments
___ k. tissue that forms the internal framework of the body and works with skeletal muscle to generate movement
___ l. tissue that contains a network of elastic fibers, providing strength, elasticity, and maintenance of shape; located in the external ear
___ m. connective tissue with formed elements suspended in a liquid matrix called plasma
- blood
- fibrocartilage
- mesenchyme
- dense regular connective tissue
- lymph
- hyaline cartilage
- dense irregular connective tissue
- areolar connective tissue
- reticular connective tissue
- bone (osseous tissue)
- elastic connective tissue
- elastic cartilage
- adipose tissue
3 a. the tissue from which all other connective tissues eventually arise
5 b. connective tissue with a clear, liquid matrix that flows in lymphatic vessels
8 c. connective tissue consisting of several kinds of cells, containing all three fiber types randomly arranged, and found in the subcutaneous layer deep to the skin
13 d. a loose connective tissue specialized for triglyceride storage
9 e. tissue that contains reticular fibers and reticular cells and forms the stroma of certain organs such as the spleen
7 f. tissue with irregularly arranged collagen fibers found in the dermis of the skin
11 g. tissue found in the lungs that is strong and can recoil back to its original shape after being stretched
6 h. tissue that affords flexibility at joints and reduces joint friction
2 i. tissue that provides strength and rigidity and is the strongest of the three types of cartilage
4 j. bundles of collagen arranged in parallel patterns; compose tendons and ligaments
10 k. tissue that forms the internal framework of the body and works with skeletal muscle to generate movement
12 l. tissue that contains a network of elastic fibers, providing strength, elasticity, and maintenance of shape; located in the external ear
1 m. connective tissue with formed elements suspended in a liquid matrix called plasma
