Chapter 5 Tissue Study Questions

Compare the structure of tight junctions and gap junctions. Relate their structural differences to their functional differences

+Tight junctions:region of adjacent cells are held together by fusion of the other phospholipid layer of pl. memb. - like a zipper.. difficult/impossible for substances to pass between cells -prevent digestive juices from seeping between epithelial cells and digesting the connective tissue (go thru not between) +Gap junctions: ringlike connexon --> six transmembrane proteins arranged, somewhat like the segments of an orange. small particles can pass from cytoplasm of one cell to the next thru pores. -like snaps

Which do you think would heal faster, cartilage or bone? Stratified squamous or simple columnar epithelium? Why?

cartilage heels much slower than bone and other tissues because it lacks blood supply

Tissues can grow through an increase in cell size or cell number. What are the respective terms for these two kinds of growth

cell size= hypertrophy cell number= hyperplasia

Cartilage is produced by cells called

chondroblasts

within a cartilage, cells called ________ secrete cartilage matrix

chondroblasts

Tendons and ligaments are made mainly of the protein

collagen

identify the major parts of a nerve cell

dendrites, axons, and axon terminals. They have a fourth part the cell body or soma, which carries out the basic life processes of neurons

Which tissue would be best at withstanding being pulled from several directions

dense irregular connective tissue

Tendons are composed of connective tissue.

dense regular

Distinguish between differentiation and metaplasia

differentiation: development of a more specialized form and function -ex: embryo to grownup metaplasia: change from one type of mature tissue to another -ex: young girl to mature girl vagina lining

Which of these is a primary germ layer?

ectoderm

The shape of the external ear is due to

elastic cartilage

name the four primary classes into which all adult tissues are classified;

epithelial, connective, nervous, muscular

The most abundant formed element(s) of blood is/are

erythrocytes

How do the epithelia of the esophagus and stomach differ? How does this relate to their respective functions?

esophagus - stratified squamous lines it to provide physical protection stomach - simple columnar lines it for protection secretion and absorption

________________________ prevent fluids from seeping between epithelial cells.

tight junctions

name and describe the ways the body repairs damaged tissues

Regeneration -replacement of dead or damaged cells by the same type of cells as before -restores normal function to the organ -heals most skin injuries -liver also regenerates remarkably well Phase 1: Hemostasis Phase. Phase 2: Defensive/Inflammatory Phase. Phase 3: Proliferative Phase. Phase 4: Maturation Phase. Fibrosis -replacement of damaged tissue with scar tissue -composed mainly of collagen produced by fibroblasts -scar tissue holds an organ together but does not restore normal function -heals severe cuts, burns, muscle injuries, and scarring of the lungs following tuberculosis Regeneration is the replacement of cells and fibrosis is where it involves repair by dent, forming scar tissues

what are the three fiber types found in fibrous connective tissue

reticular, collagenous, elastic

describe the typical anatomy of a gland

round base of secretory cells channeling up to a neck of cells called the duct and then further to the surface or ending area. (Exocrine gland)

The external surface of the stomach is covered by

serosa

the abdominal cavity is lined with what membrane

serous

Any epithelium in which every cell touches the basement membrane is called a/an epithelium

simple

Distinguish between a simple gland and a compound gland, and give an example of each. Distinguish between a tubular gland and an acinar gland, and give an example of each

single: single unbranched duct compound: have a branched duct single: single unbranched duct. EX: Sweat Glands compound: have a branched duct. EX: alivary glands, pancreas glands tubular gland: the duct and secretary portion are of uniform diameter. EX:glands of the stomach acinar gland: secretory cells form a dilated sac. EX: sebaceous glands

Of the three major categories of muscle, the only one that never has gap junctions is

skeletal

Classify each of the following into one of the four primary tissue classes: the skin surface, fat, the spinal cord, most heart tissue, bone, tendons, blood, and the inner lining of the stomach.

skin surface- epithelial tissue fat- connective spinal cord- nervous most heart tissue- muscular bone- connective inner lining of stomach- epithelial

osseous (bone) tissue can be of two types: __________ and __________

spongy and compact

A fixative serves to

stop tissue decay

A seminiferous tubule of the testis is lined with epithelium.

stratified cuboidal

what are the functions of connective tissue

support and protect organs, bind organs to one another

what term is used to describe the free surface of an epithelium

apical

An epithelium rests on a layer called the _______________ between its deepest cells and the underlying connective tissue

basement membrane

describe the properties that distinguish epithelium from other tissue classes

It covers the body, forms membranes (or external and internal linings,) and forms gland.

What are the three basic kinds of formed elements in blood, and what are their respective functions?

- Red Blood Cells - transporting oxygen into the body's tissues - White Blood Cells - the primary cells of the immune system, which has the important task of defending the body against viral, bacterial and parasitic attacks. - Platelets - Platelets are irregularly-shaped cell fragments that serve the primary function of hemostasis, which helps maintain the consistency of blood as well as keeping it inside of vessels, should they ever be punctured.

place the steps of tissue repair in order

- bleeding into the cut - scab formation; macrophages become active - formation of granular tissue and fibroblastic phase of repair - epithelial regeneration; fibrosis; remodeling phase

Name the three kinds of muscular tissue, describe how to distinguish them from each other in microscopic appearance, and state a location and function for each.

- skeletal- attached to bones, important for voluntary movement, limbs etc. Skeletal muscle is long, striated (dark and light lines), multi-nucleus cells - cardiac- located only in heart. Cardiac muscle has intercalated discs (gap junctions) between cardiac cells so that the electrical flow can spread within the heart for contraction; branched, one nucleus, striated - smooth- fusiform, one nucleus, NON-striated

list and classify eight types of epithelium, distinguish them from each other, and state where each type can be found in the body;

-Simple Squamous Epithelium; egg shaped; air sacs of lungs, kidney, heart, stomach, intestines; allows rapid diffusion of substances through membrane -Simple Cuboidal Epithelium- square/round cells; liver, thyroid, glands, kidney tubules, ovary; absorption and secretion -Simple Columnar Epithelium- tall narrow oval shaped; inner lining of stomach, intestines, gallbladder, uterus; absorption, secretion of mucus, movement of egg and embryo in uterine tube -Pseudostratified Columnar Epithelium- multi-layered, often goblet cells; respiratory tract, male urethra; secrets and propels mucus -Stratified Squamous Epithelium (Keratinized)- multiple cells layers becoming increasingly flat and scaly towards surface; epidermis- palms and soles; resists abrasion and penetration from pathogenic organisms, retards water loss through skin -Stratified Squamous Epithelium (Non-keratinized)- Same as keratinized epithelium but without the surface layer of dead cells; Tongue, oral mucosa, esophagus, anal canal, vagina; Resists abrasion and penetration by pathogenic organisms -Stratified Cuboidal Epithelium- Two or more layers of cells; surface cells square or round; Sweat gland ducts; egg-producing vesicles (follicles) of ovaries; sperm-producing ducts (seminiferous tubules) of testis; Contributes to sweat secretion; secretes ovarian hormones; produces sperm -Transitional Epithelium- Somewhat resembles stratified squamous epithelium, but surface cells are rounded, not flattened, and often bulge at surface; typically five or six cells thick when relaxed and two or three cells thick when stretched; cells may be flatter and thinner when epithelium is stretched (as in a distended bladder); some cells have two nuclei; Urinary tract—part of kidney, ureter, bladder, part of urethra; Stretches to allow filling of urinary tract; protects underlying tissues from osmotic damage by urine

name and describe the modes of tissue growth

1-Hyperplasia(through cell multiplication) 2-Hypertrophy(enlargement of preexisting cells) 3-Neoplasia(development of a tumor)

name and compare different modes of glandular secretion

1. Merocrine glands 2. Apocrine glands 3. holocrine glands Merocine Glands Description of secretion & example: a fluid product released through the cell membrane by exocytosis with a high enzyme content. They release secretion without loosing cytoplasm. Most secretory cells are merocrine. Mucous cells secrete mucous. E.g. salivary glands, pancreatic glands, sweat glands of the skin Apocrine Glands Description of secretion & example: Cellular product & portions of the free ends of glandular cells pinch off during secretion. They loose small portions of their cell bodies during secretion. E.g. mammary glands, ceruminous glands lining the external ear canal Holocrine Glands Description of secretion & example: Disintegrated entire cells filled with sed with secretory products. E.g. sebaceous glands of the skinecretory products. They release entire cells fill There are 2 types of Glands 1. Exocrine glands; secrete into ducts 2. Endocrine glands; secrete into tissue fluid or blood

Name the layers of a mucous membrane, and state which of the four primary tissue classes composes each layer

1. epithelium 2. areolar connective tissue (lamina propia) 3. muscularis mucosae and consist of epithelia tissue

describe or define different types of glands

A gland is an organ which produces and releases substances that perform a specific function in the body. There are two types of gland. Endocrine glands are ductless glands and release the substances that they make (hormones) directly into the bloodstream. Exocrine secrete their substances out of the body through ducts

explain how to distinguish a stratified squamous epithelium from a transitional epithelium.

ANSWER: The surface cells of transitional epithelium are rounded, not flattened, and often bulge at the surface.

What is areolar tissue? How can it be distinguished from any other kind of connective tissue?

Areolar Tissue is a common form of loose connective tissue. Numerous blood vessels

name and describe the modes and causes of tissue shrinkage and death

Atrophy -shrinkage of tissue through a loss in cell size or number -results from both normal and aging -results from lack of use of an organ -muscles display atrophy (shrinkage) from not being used and cells become smaller Necrosis -premature, pathological death of tissue due to trauma, infection, toxins, etc. Infarction -sudden death of tissue (i.e. cardiac muscle or brain tissue) -occurs when blood supply is cut off Gangrene - tissue necrosis resulting from an insufficient blood supply -usually involves infection -often occurs in diabetics -often necessitates amputation of limbs and extremities Apoptosis -programmed cell death -normal death of cells that have completed their function and best serve the body by dying and getting out of the way -cells undergoing apoptosis shrink and are quickly phagocytized by macrophages and other cells

The epithelium of the respiratory tract is mostly of the pseudostratified columnar ciliated type, but in the alveoli—the tiny air sacs where oxygen and carbon dioxide are exchanged between the blood and inhaled air—the epithelium is simple squamous. Explain the functional significance of this histological difference. That is, why don't the alveoli have the same kind of epithelium as the rest of the respiratory tract?

Because the cells have to be very thin in order for O2 and CO2 to be exchanged with the blood. Columnar cells are too big and thick and substances cannot move through them. Squamous cells allow for quick and easy diffusion across membranes

which tissue is the most abundant, widely distributed, and histologically variable of the primary tissue

CONNECTIVE

FALSE- In all connective tissues, the matrix occupies more space than the cells do

CORRECT- ADIPOSE TISSUE is an exception; cells ( not the matrix) constitute most of it's volume

FALSE- the basal cells of a pseudostratified columnar epithelium contact the basement membrane

CORRECT- ALL of them contact the basement membrane

FALSE- Adipocytes are limited to adipose tissue

CORRECT- Adipocytes are also found in areolar tissue, either singly or in small clusters

FALSE- Nerve and muscle cells are the body's only electrically excitable cells.

CORRECT- Excitability is characteristic of all living cells, but most highly developed in nerve and muscle cells

FALSE- The secretions of a gland are produced by the cells of its stroma

CORRECT- Glandular secretions are produced by the cells of the parenchyma; the stroma is nonsecretory supportive connective tissue

FALSE- The development of mature tissue types from the immature tissues of a neonate (newborn) is called neoplasia.

CORRECT- Neoplasia is abnormal tissue growth such as tumors; development of mature tissue types from nonspecialized tissues is called DIFFERENTITATION

FALSE- Cartilage is always covered by a fibrous perichondrium

CORRECT- Perichondrium is lacking from fibrocartilidge and from hyaline articular cartilage

FALSE- The esophagus is protected from abrasion by a keratinized stratified squamous epithelium

CORRECT- The esophogeal epithelium is NON Keratinized

FALSE- Skeletal muscle is defined by the fact that it is always attached to bones.

CORRECT- There are a few cases of skeletal muscles not attached to the bone

FALSE- Tight junctions function primarily to prevent cells from pulling apart.

CORRECT- Tight junctions serve mainly to restrict the passage of material between cells

Describe some similarities, differences, and functional relationships between hyaline cartilage and bone.

Cartilage and bone are both modified rigid forms of connective tissue, which was covered in the topic on tissue types. Connective tissue has two main consitutents - cells and extracellular material. the extracellular material determines the physical properties of the supporting tissue. Extracellular material (ground substance) contains glycosoaminoglycans (GAG), fibres and structural glycoproteins. Cartilage is a strong, flexible and semi-rigid supporting tissue. It can withstand compression forces, and yet it can bend. It is important in forming a template for the growth and development of long bones. And cartilage persists in regions such as the ends of bones (articular cartilage), the walls of airways (nose, trachea, larynx and bronchi). The GAG is chondroitin sulphate, which is rubbery, and provides cartilage with resilience, The fibres are either collagen, or a mixture of collagen and elastin fibres which provide cartilage with tensile strength, and elasticity respectively. Bone is rigid, mainly because the extracellular matrix is calcified.

List the cell and fiber types found in fibrous connective tissues and state their functional differences.

Collagen fibers: -most abundant of the bodies proteins (25%) -tough,flexible, and resistant to stretching -tendons,ligaments, and deep layer of skin are mostly collagen -less visible in matrix of cartilage and bone have glistening white appearance often called white fibers Reticular Fibers: -thin collagen fibers coated with glycoprotein -from framework of such organs as spleen and lymph nodes Elastic Fibers: -thinner than collagenous fibers -branch and rejoin eachother -made of protein called elastin -allows stretch and recoil (Type of connective tissue in lungs) allows skin, arteries, to spring back after being stretched -yellow fibers - fresh elastic fibers

Discuss the difference between dense regular and dense irregular connective tissue as an example of the relationship between form and function

Dense Regular tissue is densely packed and has parallel collagen fibers and are tendons and ligaments. Dense irregular connective tissue is also densely packed but is randomly arranged. it also has collagen fibers but few visible cells. Dense irregular connective tissue can withstand unpredictable amounts of stress and is found in the deeper layers of skin and around organs.

name and describe the ways that a tissue can change from one type to another

Differentiation and metaplasia

define adult and embryonic stem cells and their varied degrees of developmental plasticity

Embryonic and adult. Embryonic stem cells - compose early human embryo - Totipotent stem cells - early stages of development - and have the the potential to develop into any type of fully differentiate human cell. No only cells of the later embryonic, fetal or adult body but also cells of the temporary structures of pregnancy. Totipotency is unlimiteddevelopmnet plasticity - About 4 days after fertilization the devleoping embryo enters the blastocyst stage. It is a hollow ball with an outer cell mass that helps form the placenta and other necessary organs of pregnancy and an inner cell mass that becomes the embryo itself. Pluripotent stem cells- Cells of the inner cell. Can develop into any cell type of the embryo but accessory organs or pregnancy. Developmental plasticity is already somewhat limited. Adult stem cell Occur in small number in mature organs throughout a person's life. Typically divides moitically; one of its daughter's cells remains a stem cell and the other one differentiates into a mature specialized cell. the later may replace one that has grown old or died to help with repair of damaged tissue.

How are endocrine glands different from exocrine glands

Endocrine glands are DUCTLESS

a _____________ junction is an area of attachment between two cells that is formed by a ringlike connexon

GAP

Primary ______________ layers give rise to all of the body's mature tissue

GERM

Exocrine glands that release their secretions by disintegrating are

HOLOCRINE

Goblet cells secrete

MUCOUS

Describe the differences between a mucous and a serous membrane

Mucous membranes line the body cavities that open to the outside world, whereas serous lines the ones that are closed

What do nervous and muscular tissue have in common? What is the primary function of each?

Nerve and muscle cells have a huge amount in common (nucleus, mitochondria and other organelles), however the property that they share that other cells do not have is the ability to react to electrochemical stimuli. Nervous tissue has two main functions: sensing stimuli and sending impulses to different parts of the body as a response. Muscular tissue main function is contraction

What kinds of cells compose nervous tissue, and how can they be distinguished from each other?

Nervous tissue is composed of nerve cells called Neurons. They are distinguished by its own characteristic soma size, dendritic shape, source of synaptic input, destination of axonal output, and chemistry.

describe the types and composition of the body's membranes

Serous membranes S: Simple Squamous Epithelium over connective tissue F: Secretes serous fluid L: Closed body cavities Mucous Membranes S: Epithelium over connective tissue F: Lubrication L: Linings to cavities that are open to the exterior Synovial Membranes S: Loose connective tissue with elastic and adipose tissue F: Secretes synovial fluid for lubrication L: Joints Cavities Cutaneous Membranes S: Stratified squamous epithelium over connective tissue F: Protection L: Covers Outside of Body

explain how the structural differences between epithelia relate to their functional differences

Simple: touches the basement membrane Stratified: some cells rest on top of each other (not touching basement membrane

name the three kinds of muscular tissue and describe the differences between them

The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. one nuclei. Skeletal muscle fibers occur in muscles which are attached to the skeleton. They are striated in appearance and are under voluntary control. two nuclei. Smooth- one nucleus, fusiform, NON striated cells, Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control.

name the cell types that compose nervous tissue

The actual nerve cell is the neuron. It is the "conducting" cell that transmits impulses and the structural unit of the nervous system. The other type of cell is neuroglia, or glial, cell.

What features do most or all connective tissues have in common to set this class apart from nervous, muscular, and epithelial tissue?

The features that all connective tissues share in common is Fibroblasts.

What function do keratinized and nonkeratinized stratified squamous epithelia have in common? What is the structural difference between these two? How is this structural difference related to a functional difference between them?

They both serve as a shield/protective layer. Keratinized tissue like the skin has lots of vessicles containing keratohyaline, a protein that eventually turns into keratine when the cell dies, providing that epithelium with protection and resistance to traction and friction, and it makes it impermeable. Non keratinized tissue does not offer as much protection and allows the diffusion of materials through the cell junctions and the cell's body.

When cartilage is compressed, water is squeezed out of it, and when pressure is taken off, water flows back into the matrix. This being the case, why do you think cartilage at weight-bearing joints such as the knees can degenerate from lack of exercise?

When the joint is not exercised, the cartilage cells can suffer both from an accumulation of metabolic wastes and from poor oxygen and nutrient delivery. The delivery of these metabolic requirements and the removal of wastes are both aided by water being periodically soaked up by the cartilage and squeezed out of it. Without this action, cartilage cells die and the tissue degenerates.

explain what distinguishes excitable tissues from other tissues

excitability exists in every tissue but is developed to its highest point in muscular and nervous tissues. Electrical charge difference called the membrane potential occurs across the plasma membranes of all cells. Nervous and muscular tissue respond quickly to outside stimuli by means of changes in membrane potential.

Where would areolar connective tissue be found?

fascia between muscles, surrounding blood vessels, visceral pleura

Muscle cells and axons are often called __________________ because of their shape

fibera

The collagen of areolar tissue is produced by

fibroblasts

which cartilage is characterized by bundles of coarse collagenous fibers in the matrix

fibrocartilage

What substances account for the gelatinous consistency of connective tissue ground substance?

has a gelatinous to rubbery consistency resulting from three classes of large molecules: glycosaminoglycans, proteoglycans, and adhesive glycoproteins

What is the term for a thin, stained slice of tissue mounted on a microscope slide?

histological sections

where would you find spongy bone

in the heads of long bones, within the interior of flat and irregular bones

visualize the three-dimensional shape of a structure from a two-dimensional tissue section.

longitudinal section cross/transverse section /oblique section

Osteocytes and chondrocytes occupy little cavities called

lucanae

Which types of cells are found in fibrous connective tissue

macrophages, mast cells, adipocytes, fibroblasts

Fibers and ground substance make up the _________________ of a connective tissue.

matrix (extracellular material)

Glands classified as ______ sweat glands release their secretion by exocytosis, and their primary function is to cool the body.

merocrine

The simple squamous epithelium that lines the peritoneal cavity is called

mesothelium

Membranes lining the body cavities that are open to the outside are called (respiratory and digestive)

mucous

A/An adult stem cell can differentiate into two or more mature cell types

multipotent

Any form of pathological tissue death is called

necrosis

What embryonic germ layer gives rise to nervous tissue? To the liver? To muscle?

nervous = ectoderm liver = Endoderm muscle = Mesenchyme

A woman in labor is often told to push. In doing so, is she consciously contracting her uterus to expel the baby? Justify your answer based on the muscular composition of the uterus.

no, the uterus is made of smooth muscle which is involuntary

A bone as a whole is covered with a tough fibrous layer called a(n) _________.

periosteum

describe the junctions that hold cells and tissues together

tight junctions Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid Desomosomes prevent cells from separating during contraction Gap (communicating) junctions They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.

What are tissues composed of in addition to cells?

tissues are composed of a matrix, and the matrix is composed of fibers and ground substance.

Transitional epithelium is found in

urinary system

Distinguish between simple and stratified epithelia, and explain why pseudostratified columnar epithelium belongs in the former category despite its superficial appearance.

• Simple epithelia: One cell layer thick, all cells make contact with the basement membrane. Pseudo stratified epithelia is considered a simple epithelia because, though all cells do not reach the apical surface (giving it a stratified look), all cells come in contact with the basement membrane. • Stratified epithelia: 2 to 20 or more cell layers thick. Only the lowest layer makes contact with the basement membrane.