L3: Tissues Pt. 2 Flashcards
is a viscous, slippery substance that binds cells together, lubricates joints, and helps maintain the shape of the eyeballs.
Hyaluronic acid
White blood cells, sperm cells, and some bacteria produce ___, an enzyme that breaks apart hyaluronic acid, thus causing the ground substance of connective tissue to become more liquid.
hyaluronidase
The ability to produce ___ helps white blood cells move more easily through connective tissue to reach sites of infection and aids penetration of an oocyte by a sperm during fertilization. It also accounts for the rapid spread of bacteria through connective tissue.
hyaluronidase
provides support and adhesiveness in cartilage, bone, skin, and blood vessels.
Chondroitin sulfate
The skin, tendons, blood vessels, and heart valves contain
dermatan sulfate
bone, cartilage, and the cornea of the eye contain
keratan sulfate
Also present in the ground substance are ___, which are responsible for linking components of the ground substance to one another and to the surfaces of cells.
adhesion proteins
The main adhesion protein of connective tissues is ___, which binds to both collagen fibers and ground substance, linking them together. They also attaches cells to the ground substance.
Fibronectin
used as nutritional supplements either alone or in combina tion to promote and maintain the structure and function of joint cartilage, to provide pain relief from osteoarthritis, and to reduce joint inflammation.
Chondroitin sulfate and glucosamine
Three types of fibers are embedded in the extra cellular matrix between the cells:
collagen fibers, elastic fibers, and reticular fibers
They function to strengthen and support con nective tissues
Fibers
are very strong and resist pulling or stretching, but they are not stiff, which allows tis sue flexibility.
Collagen fibers
T or F: The collagen fibers found in cartilage and bone form different associations with surrounding molecules. As a result of these associations, the collagen fibers in cartilage are surrounded by more water molecules than those in bone, which gives cartilage a more cushioning effect.
T
often occur in parallel bundles. The bundle arrangement adds great tensile strength to the tissue.
Collagen fibers
the most abundant pro tein in your body, representing about 25% of the total
Collagen
are found in most types of connective tissues, especially bone, cartilage, tendons (which attach muscle to bone), and liga ments (which attach bone to bone).
Collagen fibers
Despite their strength, ligaments (which hold bone to bone) may be stressed beyond their normal capacity. This results in a stretched or torn ligament
Sprain
is most frequently sprained
ankle joint
Because of their poor blood supply, the healing of even partially torn ligaments is a very slow process; completely torn ligaments require
surgical repair
are smaller in diameter than collagen fibers, branch and join together to form a fibrous network with in a connective tissue
elastic fibers
An elastic fiber consists of molecules of the protein ___ surrounded by a glycoprotein named ___, which adds strength and stability.
elastin; fibrillin
Because of their unique mo lecular structure, ___ are strong but can be stretched up to 150% of their relaxed length without breaking.
elastic fibers
have the ability to return to their original shape after being stretched, a property called elasticity
elastic fibers
are plentiful in skin, blood vessel walls, and lung tissue.
elastic fibers
consisting of collagen ar ranged in fine bundles with a coating of glycoprotein, provide support in the walls of blood vessels and form a network around the cells in some tissues, such as areolar connective tissue, adipose tissue, nerve fibers, and smooth muscle tissue
reticular fibers
Produced by fibroblasts, they are much thinner than collagen fibers and form branching networks.
reticular fibers
also provide support and strength
reticular fibers
Reticular fibers are plentiful in reticular connec tive tissue, which forms the ____ (supporting framework) of many soft organs, such as the spleen and lymph nodes. These fibers also help form the basement membrane.
stroma
What are the 2 major classifications of connective tissue
embryonic connective tissue and mature connective tissue
What are the 2 types of embryonic connective tissue?
A. Mesenchyme
B. Mucoid (mucous) connective tissue
What are the 3 types of mature connective tissue?
A. Connective tissue proper
B. Supporting connective tissue
C. Liquid connective tissue
Under the connective tissue proper, what are the 2 subtypes?
Loose connective tissue and dense connective tissue
Under the loose connective tissue, what are the 3 sub-subtypes?
a. Areolar connective tissue
b. Adipose tissue
c. Reticular connective tissue
Under the dense connective tissue, what are the 3 sub-subtypes?
a. Dense regular connective tissue b. Dense irregular connective tissue c. Elastic connective tissue
Under the supporting connective tissue, what are the 2 subtypes?
Cartilage and bone tissue
Under the cartilage, what are the 3 sub-subtypes?
a. Hyaline cartilage b. Fibrous cartilage c. Elastic cartilage
Under the bone tissue, what are the 2 sub-subtypes?
a. Compact bone
b. Spongy bone
Under the liquid connective tissue, what are the 2 subtypes?
Blood and lymph plasma
refers to connective tissue present in an embryo or a fetus
embryonic connective tissue
refers to connective tissue that is present at birth and persists throughout life.
Mature connective tissue
One category of mature connective tissue is ____, which is flexible and con tains a viscous ground substance with abundant fibers.
connective tissue proper
A second category of mature connective tissue is ____, which protects and supports soft tissues of the body.
supporting connective tissue
The third category of mature connective tissue is ____, which means that the extracellular matrix is liquid.
liquid connective tissue
embryonic con nective tissue is of two types:
mesenchyme and mucoid (mu cous) connectivetissue
present primarily in the embryo, the developing human from fertilization through the first two months of pregnancy
Mesenchyme
found in the fetus, the developing human from the third month of pregnancy
mucoid connective tissue
This type of connective tissue is flexible and has a viscous ground substance with abun dant fibers.
connective tissue proper
The fibers of ____ are loosely arranged between cells. The types of this fibers are areolar connective tissue, adipose tissue, and reticular connective tissue
loose connective tissue
a second type of connective tissue proper that contains more fibers, which are thicker and more densely packed, but have considerably fewer cells than loose connective tissue
Dense connective tissue
There are three types of dense connective tissue
dense regular connective tissue, dense irregular connective tissue, and elastic connective tissue
This type of ma ture connective tissue includes cartilage and bone
Supporting Connective tissue
has irregularly shaped mesenchymal cells embedded in semifluid ground substance that contains delicate reticular fibers
Mesenchyme
Location of mesenchyme
Almost exclusively under skin and along developing bones of embryo; some in adult connective tissue, especially along blood vessels.
Forms almost all other types of connective tissue
Mesenchyme
has widely scattered fibroblasts embedded in viscous, jellylike ground substance that contains fine collagen fibers.
Mucoid (mucous)connective tissue
Location of Mucoid (mucous)connective tissue
Umbilical cord of fetus.
Its function is for support.
Mucoid (mucous)connective tissue
is one of the most widely distributed connective tissues; consists of fibers (collagen, elastic, reticular) arranged randomly and several kinds of cells (fibroblasts, macrophages, plasmocytes, adipocytes, mast cells, and a few white blood cells) embedded in semifluid ground substance (hyaluronic acid, chondroitin sulfate, dermatan sulfate, and keratan sulfate).
areolar connective tissue
Location of areolar connective tissue
In and around nearly every body structure (thus, called “packing material” of the body): in subcutaneous tissue deep to skin; papillary (superficial) dermis of skin; lamina propria of mucous membranes; around blood vessels, nerves, and body organs.
Its functions are for strength, elasticity, support.
areolar connective tissue
has cells derived from fibroblasts (called adipocytes) that are specialized for storage of triglycerides (fats) as a large, centrally located droplet. Cell fills up with a single, large triglyceride droplet, and cytoplasm and nucleus are pushed to periphery of cell.
adipose tissue
T or F: With weight gain, amount of adipose tissue increases and new blood vessels form. Thus, an obese person has many more blood vessels than does a lean person, a situation that can cause high blood pressure, since the heart has to work harder.
T
Most adipose tissue in adults is
white adipose tissue
is darker due to very rich blood supply and numerous pigmented mitochondria that participate in aerobic cellular respiration. BAT is widespread in the fetus and infant; adults have only small amounts.
Brown adipose tissue (BAT)
Location of adipose tissue
Wherever areolar connective tissue is located: subcutaneous tissue deep to skin, around heart and kidneys, yellow bone marrow, padding around joints and behind eyeball in eye socket.
Reduces heat loss through skin; serves as an energy reserve; supports and protects organs. In newborns, BAT generates heat to maintain proper body temperature. Itis also an excellent source of stem cells, which are used in rejuvenation medicine to repair or replace damaged tissue.
adipose tissue
is a fine interlacing network of reticular fibers (thin form of collagen fiber) and reticular cells.
reticular connective tissue
Location of reticular connective tissue
Stroma (supporting framework) of liver, spleen, lymph nodes; red bone marrow; reticular lamina of basement membrane; around blood vessels and muscles.
Forms stroma of organs; binds smooth muscle tissue cells; filters and removes worn-out blood cells in spleen and microbes in lymph nodes.
reticular connective tissue
forms shiny white extracellular matrix; mainly collagen fibers regularly arranged in bundles with fibroblasts in rows between them. Collagen fibers (protein structures secreted by fibroblasts) are not living, so damaged tendons and ligaments heal slowly.
Dense regular connective tissue
Location of Dense regular connective tissue
Forms tendons (attach muscle to bone), most ligaments (attach bone to bone), and aponeuroses (sheetlike tendons that attach muscle to muscle or muscle to bone).
Provides strong attachment between various structures. Tissue structure withstands pulling (tension) along long axis of fibers.
Dense regular connective tissue
is made up of collagen fibers; usually irregularly arranged with a few fibroblasts
Dense irregular connective tissue
Location of dense irregular connective tissue
Often occurs in sheets, such as fasciae (tissue beneath skin and around muscles and other organs), reticular (deeper) dermis of skin, fibrous pericardium of heart, periosteum of bone, perichondrium of cartilage, articular capsules, membrane capsules around various organs (kidneys, liver, testes, lymph nodes); also in heart valves.
Provides tensile (pulling) strength in many directions.
Dense irregular connective tissue
contains predominantly elastic fibers with fibroblasts between them; unstained tissue is yellowish.
elastic connective tissue
Location of elastic connective tissue
Walls of elastic arteries and trachea, bronchial tubes within the lungs, true vocal cords, suspensory ligaments of penis, some ligaments between vertebrae.
Allows stretching of various organs; is strong and can recoil to original shape after being stretched. Elasticity is important to normal functioning of lung tissue (recoils in exhaling) and elastic arteries (recoil between heartbeats to help maintain blood flow).
elastic connective tissue
For some individuals, there are certain areas of the body where adi pose tissue persists despite dieting and exercise. These areas include the
abdomen, buttocks, thighs, arms, and breasts
available to remove fat and sculpt the body
body-contouring techniques
which literally means suctioning fat from specific areas of the body
liposuction or lipo
involves making an incision in the skin and inserting a cannula (tube) which removes the fat with the assistance of a powerful vacuum-pressure unit. After the procedure, the incision is closed with stitches.
liposuction or lipo
There are several types of liposuction available. Among these are the
Tumescent liposuction, Ultrasound-assisted liposuction (UAL), and Laser-assisted liposuction (LAL)
The most common type of liposuc tion. Large amounts of anesthetic-containing fluid are injected into the area being treated until it becomes engorged with fluid or swollen (tumescent). The solution constricts blood vessels and causes fat cells to swell, enabling the surgeon to have better control when contouring the area. The fat is then suctioned through a cannula.
Tumescent liposuction
A special cannula de livers high-frequency sound waves that liquefy the fat cells and the liquid is removed by suction.
Ultrasound-assisted liposuction (UAL)
A special cannula delivers la ser energy that liquefies the fat cells and liquid is removed by suction.
Laser-assisted liposuction (LAL)
In addition to liposuction, there are several procedures that do not require incisions or stitches. These procedures disrupt fat cells while sparing adjacent tissues, such as nerves and blood vessels. Among these are the following:
Low-level laser therapy and Ultrasound
This technique uses low-energy laser energy that is absorbed by fat cells, which are broken down. The released triglycerides are transported by the lymphoid (lymphatic) system to the liver where they are metabolized. An example is Zerona.®
Low-level laser therapy
This procedure uses ultrasound-generated en ergy to disrupt and liquefy fat cells. The released triglycerides are transported by the lymphoid (lymphatic) system to the liver, where they are metabolized. An example is Cool Sculpting.®
Ultrasound
consists of a dense network of collagen fibers or elastic fibers firmly embedded in chon droitin sulfate, a gel-like component of the ground substance
Cartilage
can endure considerably more strain than loose and dense connective tissues.
Cartilage
The strength of cartilage is due to its
collagen fibers
ability to assume its original shape after deformation
resilience
The resilience of cartilage is due to
chondroitin sulfate
has few cells and large quantities of extracellular matrix. It differs from other con nective tissue, however, in not having nerves or blood vessels in its extracellular matrix.
Cartilage
cartilage does not have a blood supply because it secretes an
antiangiogenesis factor
a substance that prevents blood vessel growth
antiangiogenesis factor
being studied as a possible cancer treatment due to its property of preventing blood vessel growth
antiangiogenesis factor
The cells of mature cartilage is called
chondrocytes
chondrocytes occur singly or in groups within spaces called ____ in the extracellular matrix
cartilage lacunae
A covering of dense irregular connective tissue called the ____ surrounds the surface of most cartilage and contains blood vessels and nerves and is the source of new cartilage cells
perichondrium
has no blood supply, it heals poorly following an injury
cartilage
T or F: The cells and collagen-embedded extracellular matrix of cartilage form a strong, firm material that resists tension (stretching), compression (squeezing), and shear (pushing in opposite directions).
T
plays an important role as a support tissue in the body. It is also a precursor to bone, form ing almost the entire embryonic skeleton
cartilage
persists after birth as the growth (epiphyseal) plates within bone that allow bones to increase in length during the growing years. It also persists throughout life as the lubricated articular surfaces of most joints.
cartilage
There are three types of cartilage:
hyaline cartilage, fibrous cartilage, and elastic cartilage
Metabolically, ____ is a relatively inactive tissue that grows slowly.
cartilage
When injured or inflamed, cartilage repair proceeds slowly, in large part because cartilage is
avascular
The growth of cartilage follows two basic patterns
interstitial growth and appositional growth
there is growth from within the tissue. In this type of growth pattern, the cartilage increases rapidly in size due to the division of existing chondrocytes and the continuous deposition of increasing amounts of extracellular matrix by the chondrocytes. As the chondrocytes synthesize new matrix, they are pushed away from each other. These events cause the cartilage to expand from within like bread rising
interstitial growth
This growth pattern occurs while the cartilage is young and pliable, during childhood and adolescence
interstitial growth
there is growth at the outer surface of the tissue. When cartilage grows by ap positional growth, cells in the inner cellular layer of the peri chondrium differentiate into chondroblasts. As differentiation continues, the chondroblasts surround themselves with extra cellular matrix and become chondrocytes. As a result, matrix accumulates beneath the perichondrium on the outer surface of the cartilage, causing it to grow in width
appositional growth
starts later than interstitial growth and continues through ado lescence
appositional growth
make up the skeletal system
Cartilage, joints, and bones
supports soft tissues, protects delicate structures, and works with skeletal muscles to generate movement
skeletal system
store calcium and phospho rus
bones
bones houses ____ which produces blood cells
red bone marrow
bones contains ____ which is a storage site for triglycerides
yellow bone marrow
are organs composed of several different connective tissues, including bone (osseous) tissue, the peri osteum, red and yellow bone marrow, and the endosteum
bones
a membrane that lines a space within bone that stores yellow bone marrow
endosteum
is classified as either compact or spongy, depending on how its extracellular matrix and cells are organized.
bone tissue
The basic unit of compact bone is an
osteon or haversian system
Each osteon has four parts:
bone lamellae, bone lacunae, bone canaliculi, and osteonic canal
are concentric rings of extracellular matrix that consist of mineral salts (mostly calcium and phosphates), which give bone its hardness and compressive strength, and collagen fibers, which give bone its tensile strength. They are responsible for the compact nature of this type of bone tissue.
bone lamellae
are small spaces between bone lamellae that contain mature bone cells called osteocytes.
bone lacunae
mature bone cells is called
osteocytes
Projecting from the bone lacunae are____, networks of minute canals containing the processes of osteocytes. It provide routes for nutrients to reach osteocytes and for wastes to leave them
bone canaliculi
contains blood vessels and nerves.
osteonic canal
lacks osteons. Rather, it consists of columns of bone called bone trabeculae
Spongy bone
contain bone lamellae, osteocytes, bone lacunae, and bone canaliculi.
bone trabeculae
Spaces between bone trabeculae are filled with
red bone marrow
contains a resilient gel as ground substance and appears in the body as a bluish-white, shiny substance (can stain pink or purple when prepared for microscopic examination; fine collagen fibers are not visible with ordinary staining techniques); prominent chondrocytes are found in cartilage lacunae surrounded by perichondrium (exceptions: articular cartilage in joints and cartilage of growth (epiphyseal) plates, where bones lengthen during growth).
hyaline cartilage
location of hyaline cartilage
Most abundant cartilage in body; at ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, embryonic and fetal skeleton
Provides smooth surfaces for movement at joints, flexibility, and support; weakest type of cartilage and can be fractured.
hyaline cartilage
has chondrocytes among clearly visible thick bundles of collagen fibers within extracellular matrix; lacks perichondrium.
Fibrous cartilage
location of Fibrous cartilage
Pubic symphysis (where hip bones join anteriorly), intervertebral discs, menisci (cartilage pads) of knee, portions of tendons that insert into cartilage.
Support and joining structures together. Strength and rigidity make it the strongest type of cartilage.
Fibrous cartilage
has chondrocytes in threadlike network of elastic fibers within extracellular matrix; perichondrium present.
elastic cartilage
location of elastic cartilage
Lid on top of larynx (epiglottis), part of external ear (auricle), auditory tubes.
Provides strength and elasticity; maintains shape of certain structures.
elastic cartilage
consists of osteons that contain bone lamellae, bone lacunae, osteocytes, bone canaliculi, and osteonic canals
Compact bone tissue
consists of thin columns called bone trabeculae; spaces between bone trabeculae are filled with red bone marrow.
spongy bone tissue
locations of compact and spongy bone tissue
Both compact and spongy bone tissue make up the various parts of bones of the body.
Support, protection, storage; houses blood-forming tissue; serves as levers that act with muscle tissue to enable movement. Support, protection, storage; houses blood-forming tissue; serves as levers that act with muscle tissue to enable movemen
Compact and spongy bone tissue
consists of blood plasma and formed elements: red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes).
Blood
Location of Blood
Within blood vessels (arteries, arterioles, capillaries, venules, veins), within chambers of heart.
Red blood cells: transport oxygen and some carbon dioxide; white blood cells: carry on phagocytosis and mediate allergic reactions and immune system responses; platelets: essential for blood clotting.
blood
has a liq uid as its extracellular matrix.
liquid connective tissue
one of the liquid connective tis sues has a liquid extracellular matrix called blood plasma and formed elements
blood
is a pale yellow fluid that consists mostly of water with a wide variety of dissolved substances—nutrients, wastes, enzymes, plasma pro teins, hormones, respiratory gases, and ions.
blood plasma
Suspended in the blood plasma are
formed elements
composed of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes)
formed elements
transport oxygen to body cells and remove some carbon dioxide from them
red blood cells
are involved in phagocyto sis, immunity, and allergic reactions
white blood cells
participate in blood clotting
platelets
is the liquid connective tissue that flows in lymphatic vessels.
lymph plasma
consists of several types of cells in a clear liquid ex tracellular matrix that is similar to blood plasma but with much less protein. The composition of it varies from one part of the body to another.
lymph plasma
lymph plasma leaving lymph nodes includes many ____, a type of white blood cell, in contrast to lymph plasma from the small intestine, which has a high content of newly ab sorbed dietary lipids
lymphocytes
are flat sheets of pliable tissue that cover or line a part of the body.
Membranes
The majority of membranes consist of an epithelial layer and an underlying connective tissue layer and are called
Epithelial Membranes
The principal epithelial membranes of the body are
mucous membranes, serous membranes, and the cutaneous membrane, or skin
Another type of membrane, a ___ membrane, lines joints and contains connective tissue but does not contain epithelium.
synovial
lines a body cavity that opens directly to the exterior.
Mucous membrane or mucosa
also line the entire digestive canal, respiratory, and genital tracts, and much of the urinary tract. They consist of a lining layer of epithelium and an underlying layer of connective tissue.
Mucous membranes
The ___ of a mucous membrane is an important feature of the body’s defense mechanisms because it is a barrier that microbes and other pathogens have difficulty penetrating.
epithelial layer
Usually, tight junctions connect the cells, so materi als cannot leak in between them. Goblet cells and other cells of the epithelial layer of a mucous membrane secrete mucus, and this slippery fluid prevents the cavities from drying out.
Mucous membranes
Goblet cells and other cells of the epithelial layer of a mucous membrane secrete ____, and this slippery fluid prevents the cavities from drying out. It also traps particles in the respiratory passageways and lubricates food as it moves through the digestive canal.
mucus
secretes some of the enzymes needed for digestion and is the site of food and fluid absorption in the gas trointestinal tract
epithelial layer
vary greatly in different parts of the body. For example, the mucous membrane of the small intestine is nonciliated simple colum nar epithelium, and the large airways to the lungs consist of ciliated pseudostratified columnar epithelium
epithelia of mucous membranes
The connective tissue layer of a mucous membrane is areolar connective tissue and is called the
lamina propria
supports the epithelium, binds it to the underlying structures, allows some flexibility of the membrane, and af fords some protection for underlying structures. It also holds blood vessels in place and is the vascular source for the over lying epithelium
lamina propria
diffuse from the lamina propria to the covering epithelium; carbon dioxide and wastes diffuse in the opposite direction.
Oxygen and nutrients
lines a body cavity that does not open directly to the exterior (thoracic or abdominal cavities), and it covers the organs that are within the cavity.
serous membrane or serosa
consist of areolar connective tissue covered by mesothelium (simple squa mous epithelium)
serous membrane or serosa
serous membranes have two layers:
parietal layer and visceral layer
The layer attached to and lining the cavity wall is called the
parietal layer
the layer that covers and adheres to the organs within the cavity is the
visceral layer
The mesothelium of a serous membrane secretes ____, a watery lubricant that allows organs to glide easi ly over one another or to slide against the walls of cavities.
serous fluid
the serous membrane lining the thoracic cavity and covering the lungs is the
pleura
The serous membrane lining the heart cavity and covering the heart is the
pericardium
The serous membrane lining the abdominal cavity and covering the abdominal organs is the
peritoneum
covers the entire surface of the body and consists of a superficial portion called the epidermis and a deeper portion called the dermis
cutaneous membrane or skin
consists of keratinized stratified squamous epithelium, which protects underlying tissues.
epidermis
consists of dense irregular connective tissue and areolar connective tissue
dermis
line the cavities (articular cavities) of partially to freely movable joints.
Synovial membranes
line struc tures that do not open to the exterior.
Synovial membranes
they lack an epithelium and are therefore not epithelial membranes.
Synovial membranes
Synovial membranes are composed of a discontinuous layer of cells called ___, which are closer to the articular cavity (space between the bones), and a layer of connective tissue (areolar and adipose) deep to the synoviocytes
synov iocytes
Synoviocytes secrete some of the components of
Synovial fluid
lubricates and nourishes the cartilage covering the bones at movable joints and contains macrophages that remove microbes and debris from the joint cavity
Synovial fluid
a flat sheet of pliable tissues that covers or lines a part of the body.
membrane
line body cavities that open to the outside and line organs in these cavities.
Mucous membranes
line body cavities that do not open directly to the outside and cover organs in those cavities.
Serous membranes
covers the surface of the body that contain an articular cavity.
skin
line joints that contain an articular cavity.
Synovial membranes
consists of elongated cells called muscle fibers or myocytes that can use ATP to generate force. As a re sult, it produces body movements, maintains posture, and generates heat. It also provides protection
Muscular tissue
Based on location and certain structural and functional features, mus cular tissue is classified into three types:
skeletal, cardiac, and smooth
consists of long, cylindrical, striated fibers (striations are alternating light and dark bands within fibers that are visible under a light microscope). Skeletal muscle fibers vary greatly in length, from a few centimeters in short muscles to 30–40 cm (about 12–16 in.) in the longest muscles. A muscle fiber is a roughly cylindrical, multinucleated cell with nuclei at the periphery. Skeletal muscle is considered voluntary because it can be made to contract or relax by conscious control.
Skeletal muscle tissue
Location of Skeletal muscle tissue
Usually attached to bones by tendons.
Motion, posture, heat production, protection
Skeletal muscle tissue
consists of branched, striated fibers with usually only one centrally located nucleus (occasionally two). Attach end to end by transverse thickenings of plasma membrane called intercalated discs, which contain desmosomes and gap junctions. Desmosomes strengthen tissue and hold fibers together during vigorous contractions. Gap junctions provide route for quick conduction of electrical signals (muscle action potentials) throughout heart. Involuntary (not conscious) control.
Cardiac muscle tissue
Location of Cardiac muscle tissue
Heart wall.
Pumps blood to all parts of body.
Cardiac muscle tissue
consists of nonstriated fibers (lacking striations, hence the term smooth). Smooth muscle fiber is a small spindle-shaped cell thickest in middle, tapering at each end, and containing a single, centrally located nucleus. Gap junctions connect many individual fibers in some smooth muscle tissue (for example, in wall of intestines). Usually involuntary; can produce powerful contractions as many muscle fibers contract in unison. Where gap junctions are absent, such as iris of eye, smooth muscle fibers contract individually, like skeletal muscle fibers.
Smooth muscle tissue
location of Smooth muscle tissue
Iris of eyes; walls of hollow internal structures such as blood vessels, airways to lungs, stomach, intestines, gallbladder, urinary bladder, and uterus.
Motion (constriction of blood vessels and airways, propulsion of foods through digestive canal, contraction of urinary bladder and gallbladder).
Smooth muscle tissue
consists of only two principal types of cells: neu rons and neuroglia
ner vous tissue
are sensitive to various stimuli.
Neurons or nerve cells
They convert stimuli into electrical signals called ____ and conduct these action potentials to other neurons, to muscle tissue, or to glands.
nerve action potentials (nerve impulses)
Most neurons consist of three basic parts:
a cell body and two kinds of cell processes— dendrites and axons
contains the nucleus and other organelles
cell body
are tapering, highly branched, and usually short cell processes (extensions). They are the major receiving or input portion of a neuron.
Dendrites
is a single, thin, cylindrical process that may be very long. It is the output por tion of a neuron, conducting nerve impulses toward another neuron or to some other tissue.
axon
do not generate or conduct nerve impulses, these cells do have many important supportive functions.
neuroglia
Neurons and muscle fibers are considered ____ because they exhibit electrical excitability
excitable cells
the ability to respond to certain stimuli by producing electrical signals such as action potentials
electrical excitability
can propagate (travel) along the plasma membrane of a neuron or muscle fiber due to the pres ence of specific voltage-gated ion channels
action potentials
When an action po tential forms in a neuron, the neuron releases chemicals called ___, which allow neurons to communicate with other neurons, muscle fibers, or glands
neurotransmitters
consists of (1) neurons (nerve cells), which consist of cell body and processes extending from cell body (one to multiple dendrites and a single axon); and (2) neuroglia, which do not generate or conduct nerve impulses but have other important supporting functions.
Nervous tissue
Location of nervous tissue
Nervous system.
Exhibits sensitivity to various types of stimuli; converts stimuli into nerve impulses (action potentials); conducts nerve impulses to other neurons, muscle fibers, or glands.
Nervous tissue
is the replacement of worn-out, damaged, or dead cells.
tissue repair
New cells originate by cell division from the ___, the supporting connective tissue, or from the ____, cells that constitute the functioning part of the tissue or organ.
stroma; parenchyma
endure considerable wear and tear (and even injury) in some locations, have a continuous capacity for renewal.
Epithelial cells
In some cases, immature, undifferentiated cells called ____ divide to replace lost or damaged cells
stem cells
has a relatively poor capacity for renewal of lost cells.
Muscular tissue
Even though skeletal muscle tissue contains stem cells called ____, they do not divide rapidly enough to replace extensively damaged muscle fibers.
satellite cells
lacks satellite cells, and existing cardiac muscle fibers do not undergo mitosis to form new cells.
Cardiac muscle tissue
can proliferate to some extent, but they do so much more slowly than the cells of epithelial or connective tissues
Smooth muscle fibers
has the poorest capacity for renewal
Nervous tissue
The restoration of an injured tissue or organ to normal struc ture and function depends entirely on whether ___ are active in the repair process
parenchymal cells
If parenchymal cells accomplish the repair, ____ is possible, and a near-perfect reconstruction of the injured tissue may occur.
tissue regeneration
However, if fi broblasts of the stroma are active in the repair, the replacement tissue will be a new
connective tissue
The fibroblasts synthesize collagen and other extracellular matrix materials that aggregate to form scar tissue, a process known as
fibrosis
When tissue damage is extensive, as in large, open wounds, both the connective tissue stroma and the parenchymal cells are active in repair; ___ divide rapidly, and new collagen fibers are manufactured to provide structural strength.
fibroblasts
also sprout new buds to supply the healing tissue with the materials it needs
blood capillaries
All these processes create an actively growing connective tissue called
granulation tissue
This new tissue forms across a wound or surgical incision to provide a framework (stroma) that supports the epithelial cells that migrate into the open area and fill it. The newly formed granulation tissue also secretes a fluid that kills bacteria.
granulation tissue
At times, a small but significant number of patients develop a complication of surgery called, the partial or complete separation of the outer layers of a sutured incision. A common cause is surgical error in which sutures or staples are placed too far apart, too close to the incision edges, or under too much pressure. It can also occur if sutures are removed too early or if there is a deep wound infection. Other contributing factors are age,chemotherapy, coughing, straining, vomiting, obesity, smoking, and use of anticoagulants such as aspirin.
wound dehiscence
A major complication of wound dehiscence is the protrusion of an organ through the open wound, especially the intestines. This can lead to ___ (inflammation of the peritoneum) and ___ (shock that results from bacterial toxins due to vasodilation).
peritonitis; septic shock
Three factors affect tissue repair:
nutrition, blood circulation, and age
is vital because the healing process places a great demand on the body’s store of nutrients. Adequate protein in the diet is important because most of the structural compo nents of a tissue are proteins. Several vitamins also play a direct role in wound healing and tissue repair.
Nutrition
directly affects the normal production and maintenance of matrix materials, especially collagen, and strengthens and pro motes the formation of new blood vessels. In a person with vi tamin C deficiency, even superficial wounds fail to heal, and the walls of the blood vessels become fragile and are easily ruptured.
Vitamin C
is essential to transport oxygen, nutrients, antibodies, and many defensive cells to the injured site. The blood also plays an important role in the removal of tissue fluid, bacteria, foreign bodies, and debris, elements that would otherwise interfere with healing.
Proper blood circulation
Scar tissue can form ___, abnormal joining of tissues
adhesions
commonly form in the abdomen around a site of previous inflammation such as an inflamed appendix, and they can develop after sur gery.
adhesions
they can decrease tissue flexibility, cause obstruction (such as in the intestine), and make a subsequent operation, such as a cesar ean section (C-section), more difficult. In rare cases adhesions can result in infertility.
adhesions
the surgical release of adhesions, may be required.
adhesiotomy
get progressively thinner and connective tissues become more fragile with aging. This is evidenced by an increased incidence of skin and mucous membrane disorders, wrinkles, more sus ceptibility to bruises, increased loss of bone density, higher rates of bone fractures, and increased episodes of joint pain and disorders.
epithelial tissues
There is also an effect of aging on ___ as evidenced by loss of skeletal muscle mass and strength, decline in the efficiency of pumping action of the heart, and decreased activity of smooth muscle–containing organs, for example, organs of the digestive canal.
muscle tis sue
the most abundant sugar in the body, plays a role in the aging process.
Glucose
responsible for the strength of tendons, increase in number and change in quality with aging. Changes in the collagen of arterial walls affect the flexibility of arteries as much as the fatty deposits associated with atherosclerosis
Collagen fibers
another extracellular component, is responsible for the elasticity of blood vessels and skin. It thickens, fragments, and acquires a greater affinity for calcium with age—changes that may also be associated with the development of atherosclerosis.
Elastin
Disorders of epithelial tissue are mainly specific to individual organs, such as ____, which erodes the epithelial lining of the stomach or small intestine.
peptic ulcer disease (PUD)
The most prevalent disor ders of connective tissues are
autoimmune diseases
diseases in which antibodies produced by the immune system fail to dis tinguish what is foreign from what is self and attack the body’s own tissues.
autoimmune diseases
One of the most common autoimmune disorders is ___, which attacks the synovial membranes of joints.
rheumatoid arthritis
is a chronic inflammatory disease of connec tive tissue occurring mostly in nonwhite women during their childbearing years. It is an autoimmune disease that can cause tissue damage in every body system. The disease, which can range from a mild condition in most patients to a rapidly fatal disease, is marked by periods of exacerbation and remission. The prevalence of SLE is about 1 in 2000, with females more likely to be afflicted than males by a ratio of 8 or 9 to 1.
Systemic lupus erythematosus (SLe) or lupus
Signs and symptoms include painful joints, low grade fever, fatigue, mouth ulcers, weight loss, enlarged lymph nodes and spleen, sensitivity to sunlight, rapid loss of large amounts of scalp hair, and anorexia.
Systemic lupus erythematosus (SLe) or lupus
A distinguishing feature of lupus is an eruption across the bridge of the nose and cheeks called a
butterfly rash
The most se rious complications of the disease involve inflammation of the kidneys, liver, spleen, lungs, heart, brain, and gastrointestinal tract. Because there is no cure for SLE, treatment is supportive, including anti-inflammatory drugs such as aspirin, and immu nosuppressive drugs.
Systemic lupus erythematosus (SLe) or lupus
Other skin lesions may occur, includ ing blistering and ulceration.
Systemic lupus erythematosus (SLe) or lupus
A decrease in the size of cells, with a subsequent decrease in the size of the affected tissue or organ.
atrophy
Increase in the size of a tissue because its cells enlarge without undergoing cell division.
hypertrophy
An immune response of the body directed at for eign proteins in a transplanted tissue or organ; immunosuppressive drugs, such as cyclosporine, have largely overcome tissue rejection in heart-, kidney-, and liver-transplant patients
tissue rejection
The replacement of a diseased or injured tissue or organ. The most successful transplants involve use of a person’s own tissues or those from an identical twin.
tissue transplantation
The replacement of a diseased or injured tissue or organ with cells or tissues from an animal. Porcine (from pigs) and bovine (from cows) heart valves are used for some heart-valve replacement surgeries.
Xenotransplantation
