Chapter 4 Study Guide Flashcards
Know the functions of cell junctions:
mechanical anchorage and communication
Which junction is involved in communication rather than achorage?
The gap junction
Purpose of Tight Junctions:
Know that this is the junction most important if preventing passage of substance between cells. the places that these junctions are most imporatant are where you would not want leakage across an epithelial cell layer. For example: leakage of urine through the epithelium of the bladder, leakage of the acid contents of the stomach, leackage of unprocessed food through the gut.
Where would you most want a tight junction?
Places where you would not want leakage across an epithelial cell later, e.g. leakage of acid contents of the stomach
What is the main purpose of the tight junction?
most important in preventing passage of substance between cells.
Which junction is this: [PICTURE NEEDED]
Tight Junction
Purpose of Adherens Junctions:
Join cells together by transmembrane proteins called cadherins. Also attach the microfilaments of the cytoskeleton to the plasma membrane. This microfilament component forms a thick protein belt around the cell. Functionally important in resisting cell tearing during contractile activity e.g. in uterus or when food is moving through gut.
What are microfilaments made of?
Actin
Which junction is this: [PICTURE NEEDED]
Adherens Junctions
When do you most want an Adherens Junction?
Functionally important in resisting cell tearing during contractile activity, e.g. in uterus or when food is moving through gut.
Purpose of Desmosomes:
Also (like adherins junctions) join cells together by transmembrane proteins call cadherins. Attach to the cytoskeleton via intermediate filaments called keratins. Very common in the skin and in cardiac muscle cells.
Which junction is this: [PICTURE NEEDED]
Desmosomes
Purpose of Hemidesmosomes:
Similar to desmosomes but tey appear like half a desmosome since they occure when attaching a single cell to the basal lamina. The transmembrane proteins are called integrins.
Define term: cadherins
transmembrane proteins joining cells in the adherens junctions
Define term: microfilaments of the cytoskeleton
You will find microfilaments in most cells. They are the partner of microtubules. They are long, thin, and stringy proteins (mainly actin, but also myosin) compared to the rounder, tube-shaped microtubules. We’d like to say you can find them here or there, but they are everywhere in a cell. They work with microtubules to form the structure that allows a cell to hold its shape, move itself, and move its organelles.
Define term: Keratins
intermediate filaments that attach the desmosomes to the cytoskeleton
Define term: integrins
a family of trasmembrane proteins that function in cell adhesion; they are present in hemidesmosomes, whic anchor cells to a basement membrane, and they mediate adhesion of neutrophils to endothelial cells during emigration.
Purpose of Gap Junctions:
These are the junctions involved in cell/cell communication. Form structures called connexons. These are made up of proteins called connexins. They change conformation to open and close a central pore. Allow for transport of substances such as ions.
Define terms: connexons
Gap junctions form structures called connexons, which are made up of proteins called connexins
Define epithelial tissue:
A continuous sheet of cells with continuous borders that line a surface
Give examples of external locations for epithelial tissues
skin, cornea
Give examples of internal locations for epithelial tissues
digestive tract, peritoneal cavity, trachea, urinary system, hepatocytes (liver cels) and bile ducts, kidney duct cells
Where is the apical surface of the epithelial cell plasma membrane?
surface in contact with air of fluid (externally facing)
Where is the lateral surface of the epithelial cell plasma membrane?
surface in contact with adjacent epithelial cells
Where is the basal surface of the epithelial cell plasma membrane
surface in contact with the basal lamina which is in contact with the connective tissue
Kow the method of classification of epithelia
number of layers, shape of the outermost layer of cells, the exceptions
What are the different classifications of epithelia based on the number of layers?
simple, stratified, pseudostratified
What are the different classifications of epithelia based on the shape of the outermost layer of cells
squamous, cuboidal, culumnar
Define transitional epithelia:
Transitional epithelium (also known as urothelium) is a type of tissue consisting of multiple layers of epithelial cells which can contract and expand.
NAMES AND EXAMPLES OF LOCATION FOR EACH EPITHELIAL CATAGORY
1) Simple Squamous Epithelium, lines the cardiovascular and lymphatic system, where it is known as endothelium. Forms the epithelial layer of serous membranes, called mesothelium.
2) Simple Cuboidal Epithelium, covers surface of ovary, lines anterior surgace of capsule of lens of the eye, lines kindey tubules and smaller ducts of many glands.
3) Nonciliated Simple Columnar Epithelium, lines gastrointestinal tract, ducts of many glands, and gallbladder
4) Ciliated Simple Columnar Epithelium, lines some bronchioles of respiratory tract, uterine tubes, uterus, some paranasal sinuses
5) Pseudostratified Columnar Epithelium, cilated variety lines airways of most of upper resipiratory tract, nonciliated variety lines larger ducts of many glands, epididymus and part of male urethra
6) Stratified Squamous Epithelium, keratinized variety forms superficial layer of skin, nonkeratinized variety lines wet surfaces and covers tongue
7) Stratified Cuboidal Epithelium, ducts of adult sweat glands and esophageal glands, part of male urethra
8) Stratified Columnar Epithelium, lines part of urethra, large excretory duct of some glands, smal areas in anal mucous membrane
9) Transitional Epithelium, lines urinary bladder and portions of ureters and urethra
Know the functions of epithelia:
protective functions, transport functions, reproductive functions
What is the difference between and endocrine and an exocrine gland:
Endrocrine glands secrete directly into the blood stream, exocrine glands have a series of ducts to get their secretion into the bloodstream.
Know the methods of classification of exocrine glands
a) according to branching of the ducts – simple or compound
b) according to the structure of the secretory units – tubular, acinar, alveolar
c) according to the type of secretion, mucous, serous, or mixed
d) according to the method of secretion – merocrine, apocrine, holocrine.
Define: merocrine
secretion in granules released by exocytosis
Define: Aprocrine
when the secretion is released, some of the plasma membrane is lost with it, e.g. sweat glands
Define: Holocrine
whole cell with secretory product released into duct, e.g. sebacious gland
DIFFERENT EXOCRINE GLANDS AND DEETS
simple or compound – to do with branching of ducts
tubular, acinar, or alvelolar - to do with structure of secretory units. tutlar have secretory units arranged in tube0like structures. Acinar (narrow and short lumen) and alveolar (distended lumen) glands have secretory units arranged in a rounded structure
mucous, serous, or mixed – to do with type of secretion. Mucous secrete viscous glycoproteis, serous secretes watery secretions, full of enymes
merocinr, apocrine, or holocrine – to do with method of secretion – merocine secretes in granules released by exocytosis. apocrine secretion is released and some of the plams membrane in lost with it (e.g. sweat glands). holocine – whole cell with secretory product released into duct (e.g. sebaceous gland)
Functions of connective tissue:
a) to provide support, strength, elasticity, and incompressibility
b) to provide an environment for infiltration of immune cells
c) important in defense, inflammatory responses, and tissue repair.
What components of connective tissue are capable of performing the function of providing support, strength, elasticity, and incompressibility:
fibroblasts, adipocytes, reticular and collagen fibers
What components of connective tissue are capable of performing the function of providing an environment for infiltration of immune cells:
“ground substance”
What components of connective tissue are capable of performing the fuction of assisting in defense, inflammatory responses, and tissue repair:
macrophages, pasma cells, other blood cells, mast cells
Define term: Fibroblasts
A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen,[1] the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
Define term: Adipocytes
fat cells in connective tissue
Define term: Macrophages
in the connective tissue, immune cells derived from blood-borne monocytes
Define term: plasma cells
in the connective tissue, immune cells that develop from B lymphocytes
Define term: mast cells
in connective tissue, produce histamine – part of defense system – overactive in allergy
Cells of connective tissue:
Fibroblasts, adipocytes, macrophages, plasma cells, mast cells, and other blood cells such as eosinophils and neutrophils which migrate into connective tissue in injury and infection.
Define term: extracellular matrix
the extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the animal cells (cytoskeleton) in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.
Extracellular matrix includes the interstitial matrix and the basement membrane.[1][page needed] Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM.[2][page needed] Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest.
Define term: glycosaminoglycan
GAGS, repeating dissacharide of two sugars. Attach to core proteins to form proteoglycans. Highly negatively charged due to presence of sulfate groups => negative charge makes them hydrophillic => draw water into the matrix resulting in a gel-like consistency, allowing GAGs to resist compressie forces
Define term: proteoglycan
a proteoglycan monomer consits of a core protein with GAG side chains. The major proteoglycan in caritlage forms large aggregates with hyaluronic acid as a backbone.
Know the names of four different glycosaminoglycans:
hyaluronic acid, chrondroitin sulfate, keratan sulfate, and dermatan sulfate
What is the only glycosaminoglycan that is unsulfated
Hyaluronic acid
What is Hyaluronic acid?
It is the viscous substance in the synovial fluid that is in synovial joins and the vitreous humor in the eye. the only glycosaminoglycan that is unsulfated.
The sulfated glycosaminoglycan chains carry a high negative charge. What is the significance of this?
hydrophilic => sucks in water, creating a gel-like consistency which allows for compression
What are the types of Fibrillar proteins?
collagens, reticular fibers (stain with silver), elastin fibers
What are collagens?
the most abundant protein in the body. Has a triple helical structure. Provide strength.
What are reticular fibers?
in fact a specific type of collagen, but classified separately because they stain with silver. Form a fishing net-like network throughout organs to hold cells in splace. Make up part of the basement membrane that underlies epithelia.
What are elastic fibers?
Made up of a protein called elastin that is cross-linked by a glycoprotein called fibrillin. Important where elasticity is required. Walls of arteries, skin, ear flaps, etc.
What are glycoproteins?
many adhesions glycoproteins are present in the matrix such as fibronectin. These help link extracellular matrix molecules to one another and to the surface of the cells.
Name the three classifications of adult connective tissue and give examples of each.
Loose (areolar CT, adipose tissue, reticular CT), dense regular (tendon) and dense irregular (capsules of organs, wall of artery, lung), and Specialized CT (Cartilage, bone, blood)
what is mesenchyme?
the embryonic tissue from which all connective tissues are derived
Define Cartilage:
a) consists of specialized cells called chrondrocytes embedded in a unique matrix
b) avascular and aneural
c) 3 different classes, hyaline, articular, and elastic cartilage/fibrocartialge
Define chondrocytes:
Cartilage is specialized connective tissue, chrondocytes embedded in a unique matrix – catilage cells
Know structural components and examples of locations of each cartilage type. How is the structure of each cartilage type useful for the particular locations?
Elastic Cartilage
Description: Chondrocytes in threadline network of elastic fibers within extracellular matrix; perichondrium present
Location: Lid of top of larync, part of external ear, auditory tubes
Function: Provides strength and elasticity, maintains shape of certain structures
Know structural components and examples of locations of each cartilage type. How is the structure of each cartilage type useful for the particular locations?
Hyaline Cartilage
Hyaline means glassy or transparent.
Description: contains a resilient gel as ground substance and appears in the body as a bluish-white, shiny substance. Fine collagen fibers are not visble with ordinary staining techniques; prominent chondrocytes are found in lacunae surrounded by perichondrium (exceptions: articular cartilage in joins and cartilage of epiphyseal plates, where bones lenthen during growth)
Location: 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
Function: Provides smooth surfaces for movement at joints, flexibility, and support; weakest type of cartilage.
Know structural components and examples of locations of each cartilage type. How is the structure of each cartilage type useful for the particular locations?
Fibrocartilage
Description: Chondrocytes scattered among clearly visible thick bundles of collagen fibers within extracellular matrix; lacks perichondrium
Location: pubic symphysis (where hip bones join anteriorly), intervertebral discs, cartilage pads of knee, portions of tendons that intert into cartilage
Function: Support and joining structures together. Strengh and rigity make it the strongest type of cartilage.
Know structural components and examples of locations of each cartilage type. How is the structure of each cartilage type useful for the particular locations?
Articular Cartilage
is found at the ends of long bones is a specialized form of hylaine cartilage.
What are the two major types of bone?
Compact bone and spongy bone
Define: Compact Bone
this is the real weight bearing bone that lays down a dense mineralized matrix
Define: Spongy Bone
this is also called trabecular or cancellous bone. Bones Marrow runs through.
Know the structural organization of cortical bone into osteons.
The basic unit of compact bone is an osteon or haversian system. Each osteon has four parts: the lamellae, the lacunae, the caniculi, and the central canal.
Define: Osteon
The basic unit of structure in adult compact bone, consisting of a central canal with its concentircally arranged lamellae, lacunae, osteocytes, and canaliculi.
Define: Central Canal
A microscopic tube running the length of the spinal cord in the gray commissure. A circular channel running longitudinally in the center of an osteon (haversian system) of mature compact bone, containing blood and lymphatic vessels and nerves.
Define: Lacuna
A small, hollow space, such as that found in bones in which the osteocytes lie
Define: Lamellae
concentric rings of hard, calcified extracellular matrix found in compact bone
Define: Cannaliculi
small channels or canals, as in bones, where they connect lacunae.
Define: Osteocyte
A mature bone cell that maintains the daily activities of bone tissue
What is blood classified as?
Liquid connective tissue
What does blood contain?
red blood cells, platelets, and white blood cells
What do red blood cells do?
Carry oxygen to the tissues
What do while blood cells do?
involved in defense/immune system
What do platelets do?
Inolved in blood clotting.
Know the major structural features and locations of the three types of muscle tissue.
Skeletal
voluntary, provide heat, allow for movement, support posture, and protection.
long striated fibers, perifpheral nuclei, attached to bones via tendons
What are the three types of muscle tissue:
Skeletal, Cardiac, and Smooth
Know the major structural features and locations of the three types of muscle tissue.
Cardiac
in heart, involuntary, pump blood.
branched, striated fibers. centrally located nuclei.
Know the major structural features and locations of the three types of muscle tissue.
Smooth
spindle shaped, non-striated with centrally located nuclei. Involuntary control. Walls of iternal organs such as blood vessels, GI tract, airways to lungs. Gall bladder, urinary bladder, uterus.
Motion e.g. constriction of blood vessels, movement of food through GI, contraction of bladder, uterus.
What is the difference between neurons and neuroglial cells?
neurns convert stimuli into electical signals while neuroglia provides structural support. Neurons much larger.
What is the function of neurons? neuroglial cells?
Neurons – the nerve cells that convert stimuli into electrical signals called action potentials. Neuroglia – cells that provide a structural support to neurons.
How do neurons and neuroglial cells differ in size?
Neurons are much larger than neuroglial cells
What is the role of the axon on a neuron?
An axon (from Greek, axis) also known as a nerve fibre; is a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron’s cell body. The function of the axon is to transmit information to different neurons, muscles and glands.
What is the role of a dendrite on the neuron?
Dendrites (from Greek δένδρον déndron, “tree”) are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. Electrical stimulation is transmitted onto dendrites by upstream neurons (usually their axons) via synapses which are located at various points throughout the dendritic tree. Dendrites play a critical role in integrating these synaptic inputs and in determining the extent to which action potentials are produced by the neuron
Define Term: Atrophy
(Science: pathology) a wasting Away, a diminution in the size of a cell, tissue, organ or part.
Define Term: Biopsy
a biopsy refers to a procedure that involves obtaining a tissue specimen for microscopic analysis to establish a precise diagnosis.
Define Term: Hypertrophy
The enlargement or overgrowth of an organ or part due to an increase in size of its constituent cells.
Define Term: Tissue Rejection
Usually used of grafts. Any process leading to the destruction or detachment of a graft or other specified structure.
Define Term: Tissue Transplantation
transference of tissue within an individual, between individuals of the same species, or between individuals of different species.
Define Term: Xenotransplantation
Xenotransplantation (xenos- from the Greek meaning “foreign”), is the transplantation of living cells, tissues or organs from one species to another
