Tissues Flashcards
Name the four basic types of Body Tissues
Body tissues are classified into four basic types based on their structure and functions:
- Epithelial tissue covers body surfaces;
lines body cavities, hollow organs, and ducts (tubes); and forms glands. - Connective tissue protects and supports the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity.
- Muscular tissue generates the physical force needed to make body structures move.
- Nervous tissue detects changes inside and outside the body and initiates and transmits nerve impulses (action potentials) that coordinate body activities to help maintain homeostasis.
Which are the two main types of Epithelial tissue?
Epithelial tissue
- Covering and lining epithelium
- Glandular epithelium
- Covering and lining epithelium forms the outer covering of the skin and the outer covering of some internal organs. It also lines body cavities; blood vessels; ducts; and the interiors of the respiratory, digestive, urinary, and reproductive systems. It makes up, along with nervous tissue, the parts of the sense organs for hearing, vision, and touch.
- Glandular epithelium makes up the secreting portion of glands, such as sweat glands.
Name the properties of the Epithelial cell
Epithelial cell - Properties
a. Membrane specializations
b. Tight connections
c. Polarized
d. Anchored to the extracellular matrix (ECM)
e. High mitotic activity (delar sig ofta)
f. Lack blood vessels
g. Sensory information – nerves
h. Cellularity
Explain Membrane specializations of Epithelial cells
Membrane specializations Epithelial cells
Explain tight connections/always a free surface of Epithelial cells
Tight connections/always a free surface
Epithelial cells are tightly connected Cell-cell-adhesion
Adhesion – proteins are anchored to the cytoskeleton
Epithelial cells can communicate through GAPjunctions
Explanation:
Epithelial cells have an apical (free) surface, which is exposed to a body cavity, lining of an internal organ, or
the exterior of the body; lateral surfaces, which face adjacent cells on either side; and a basal surface, which is attached to a basement membrane. In discussing epithelia with multiple layers, the term apical layer refers
to the most superficial layer of cells, whereas the term
basal layer refers to the deepest layer of cells. The basement membrane is a thin extracellular structure composed mostly of protein fibers. It is located between the epithelium and the underlying connective tissue layer and helps bind and support the epithelium
Explain Polarized Epithelial Cells
Epithelial cells are polarized
Explain Anchored to the extracellular matrix (ECM) - Epithelial Cells
Anchored to the extracellular matrix (ECM)
Explain High mitotic activity for Epithelial cells
Explain High mitotic activity (cell division) for Epithelial cells
Because epithelium is subject to a certain amount of wear
and tear and injury, it has a high capacity for renewal by
cell division.
Explain the meaning of that Epithelia cells are avascular.
Epithelia are avascular (a- without; vascular blood
vessels); that is, they lack blood vessels. The vessels that
supply nutrients to and remove wastes from epithelia are
located in adjacent connective tissues. The exchange of
materials between epithelium and connective tissue occurs by diffusion.
How does Epithelia cells conduct Sensory information
Sensory information Epithelia cells
Epithelia have a nerve supply.
Explain Cellularity Epithelial Cells
Cellularity Epithelial Cells
Epithelium consists largely or entirely of closely packed
cells with little extracellular material between them, and
the cells are arranged in continuous sheets, in either single or multiple layers.
What are the functions of Epithelial Tissue?
Epithelial tissues - Functions
- Barrier / Physical protection /(abrasion, dehydration, destruction)
- Control permeability – absorption/secretion, gas exchange - everything
- Reduce friction – water secretion
- Provide sensation
- Cleaning – movement of fluids over surface
- Secretion - glands
Explain the classification of epithelial tissue
Classification of epithelial tissue
Explain the differences between Simple epithelium, Pseudostratified epithelium & Stratified epithelium?
Simple epithelium, Pseudostratified epithelium & Stratified epithelium
- Simple epithelium is a single layer of cells that functions in diffusion, osmosis, filtration, secretion, and absorption. Secretion is the production and release of substances such as mucus, sweat, or enzymes. Absorption is the intake of fluids or other substances such as digested food from the intestinal tract.
- Pseudostratified epithelium (pseudo- false) appears to have multiple layers of cells because the cell nuclei lie at different levels and not all cells reach the apical surface. Cells that do extend to the apical surface may contain cilia; others (goblet cells) secrete mucus. Pseudostratified epithelium is actually a simple epithelium because all of its cells rest on the basement membrane.
- Stratified epithelium (stratum layer) consists of two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear.
Describe Simple Squamous Epithelium
Simple Squamous Epithelium - Covering and Lining Epithelium
Description: Single layer of flat cells; centrally located nucleus.
Location: Lines heart, blood vessels, lymphatic vessels, air sacs of lungs, glomerular (Bowman’s) capsule of kidneys, and inner surface of the tympanic membrane (eardrum); forms epithelial layer of serous membranes (mesothelium), such as the peritoneum.
Function: Filtration, diffusion, osmosis, and secretion in serous membranes.
Describe Simple cuboidal epithelium.
Simple cuboidal epithelium - Covering and Lining Epithelium
Description: Single layer of cube-shaped cells; centrally located nucleus.
Location: Lines kidney tubules and smaller ducts of many glands, makes up the secreting portion of some glands such as the thyroid gland, covers surface of ovary, lines anterior surface of capsule of the lens of the eye, and forms the pigmented epithelium at the posterior surface of the eye.
Function: Secretion and absorption.
Describe Nonciliated simple columnar epithelium
Nonciliated simple columnar epithelium - Covering and Lining Epithelium
Description: Single layer of nonciliated column-like cells with nuclei near bases of cells; contains goblet cells and cells with microvilli in some locations.
Location: Lines most of the gastrointestinal tract (from the stomach to the anus), ducts of many glands, and gallbladder.
Function: Secretion and absorption.
Describe Ciliated simple columnar epithelium.
Ciliated simple columnar epithelium - Covering and Lining Epithelium
Description: Single layer of ciliated column-like cells with nuclei near bases; contains goblet cells in some
locations.
Location: Lines a few portions of upper respiratory tract, uterine (fallopian) tubes, uterus, some paranasal sinuses, and central canal of spinal cord.
Function: Moves mucus and other substances by ciliary action.
Describe Pseudostratified columnar epithelium
Pseudostratified columnar epithelium - Covering and Lining Epithelium
Description: Not a true stratified tissue; nuclei of cells are at different levels; all cells are attached to basement
membrane, but not all reach the apical surface.
Location: Pseudostratified ciliated columnar epithelium lines the airways of most of upper respiratory tract; pseudostratified nonciliated columnar epithelium lines larger ducts of many glands, epididymis, and part of male urethra.
Function: Secretion and movement of mucus by ciliary action (ciliated); absorption and protection (nonciliated).
Describe Stratified Squamous Epithelium
Stratified Squamous Epithelium - Covering and Lining Epithelium
Description: Several layers of cells; cuboidal to columnar shape in deep layers; squamous cells form the apical layer and epithelium several layers deep to it; cells from the basal layer replace surface cells as they are lost.
Location: Keratinized variety forms superficial layer of skin; nonkeratinized variety lines wet surfaces, such as lining of the mouth, esophagus, part of epiglottis, part of pharynx, and vagina, and covers the tongue.
Function: Protection.
Describe Stratified cuboidal epithelium
Stratified cuboidal epithelium - Covering and Lining Epithelium
Description: Two or more layers of cells in which cells in the apical layer are cube-shaped.
Location: Ducts of adult sweat glands and esophageal glands and part of male urethra.
Function: Protection and limited secretion and absorption.
Describe Stratified columnar epithelium
Stratified columnar epithelium - Covering and Lining Epithelium
Description: Several layers of irregularly shaped cells; only the apical layer has columnar cells.
Location: Lines part of urethra, large excretory ducts of some glands such as esophageal glands, small areas in anal mucous membrane, and a part of the conjunctiva of the eye.
Function: Protection and secretion.
Describe Transitional Epithelium
Transitional epithelium - Covering and Lining Epithelium
Description: Appearance is variable (transitional); shape of cells in apical layer ranges from squamous (when stretched) to cuboidal (when relaxed).
Location: Lines urinary bladder and portions of ureters and urethra.
Function: Permits distention
Describe Endocrine glands - Glandular Epithelium
Endocrine glands - Glandular Epithelium
Description: Secretory products (hormones) diffuse into blood after passing through interstitial fluid.
Location: Examples include pituitary gland at base of brain, pineal gland in brain, thyroid and parathyroid glands near larynx (voice box), adrenal glands superior to kidneys, pancreas near stomach, ovaries in pelvic cavity, testes in scrotum, and thymus in thoracic cavity.
Function: Produce hormones that regulate various body activities.
Describe Exocrine glands - Glandular Epithelium
Exocrine glands - Glandular Epithelium
Description: Secretory products released into ducts.
Location: Sweat, oil, and earwax glands of the skin; digestive glands such as salivary glands, which secrete into mouth cavity, and pancreas, which secretes into the small intestine.
Function: Produce substances such as sweat, oil, earwax, saliva, or digestive enzymes
Which are the different types of Glandular epithelium?
Glandular epithelium
- Endocrine (ductless) /Exocrine
- Merocrine/ Holocrine (Apocrine)
- Simple/compound – tubular, alveolar, tuboalveolar
What are the three different types of muscle tissue?
Muscle tissue
- Skeletal Musle Tissues
- Cardiac Musle Tissues
- Smooth Muscle Tissues
Describe Skeletal Muscle Cells
Skeletal Muscle Cells
- Long
- Connected to bones
- Striated
- Voluntary
- More than one nucleus
- Surrounded by connective tissues
- Rich blood supply
Another word for Muscle Cell
Muscle Cell = Muscle Fiber
Explain Epimysium
Epimysium
The epimysium is the fibrous tissue envelope that surrounds skeletal muscle. It is a layer of dense irregular connective tissue which ensheathes the entire muscle and protects muscles from friction against other muscles and bones. It is continuous with fascia and other connective tissue wrappings of muscle including the endomysium and perimysium. It is also continuous with tendons, where it becomes thicker and collagenous.
Explain Perimysium – Fasicle
Perimysium – Fasicle
Perimysium is a sheath of connective tissue that groups muscle fibers into bundles (anywhere between 10 and 100 or more) or fascicles.
Recent advances in muscle physiology suggest that the perimysium plays a role in transmitting lateral contractile movements. This hypothesis is strongly supported in one exhibition of the existence of “Perimysial Junctional Plates” in ungulate Flexor carpi radialis muscles constructed by E Passerieux. The overall comprehensive organization of the perimysium collagen network, as well as its continuity and disparateness, however, have still not been observed and described thoroughly everywhere within the muscle.
Explain Endomysium
Endomysium
The endomysium, meaning within the muscle, is a wispy layer of areolar connective tissue that ensheaths each individual myocyte (muscle fiber, or muscle cell). It also contains capillaries and nerves. It overlies the muscle fiber’s cell membrane: the sarcolemma. Endomysium is the deepest and smallest component of muscle connective tissue. This thin layer helps provide an appropriate chemical environment for the exchange of calcium, sodium, and potassium, which is essential for the excitation and subsequent contraction of a muscle fiber.
Endomysium combines with perimysium and epimysium to create the collagen fibers of tendons, providing the tissue connection between muscles and bones by indirect attachment.
Which proteins play a vital part in the contraction of skeletal muscles?
Muscle filaments actin - myosin
Explain the process of muscle contraction
Muscle contraction actin – myosin - ATP
Explain the function of Troponine / tropomyosine in muscle contraction
Troponine / tropomyosine och calcium
Explain Neuromuscular junctions
Neuromuscular junction
A neuromuscular junction (or myoneural junction) is a chemical synapse formed by the contact between a motor neuron and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction.
Explain Sarcoplasmic Reticulum (SR)
Sarcoplasmic Reticulum (SR)
The sarcoplasmic reticulum (SR) is a membrane bound structure found within muscles cells, that is similar to the endoplasmic reticulum in other cells. The main function of the SR is to store calcium (Ca2+). Calcium levels are kept relatively constant, with the concentration of calcium within a cell being 100,000 times smaller than the concentration of calcium outside the cell. This means that small increases in calcium within the cell are easily detected and can bring about important cellular changes (the calcium is said to be a second messenger)
Describe Cardiac muscle cells
Cardiac muscle cells
- Branched, short
- In the heart
- Striated
- Not voluntary - involuntary
- One nucleus (usually)
- Have intercalated discs – gap junctions
Describe Smooth muscles
Smooth muscles
- Short
- Airways, blood vessels etc.
- No sarcomeres - not striated
- Not voluntary
- One nucleus
What are the major structures of the nervous system?
The nervous system includes the brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexuses, and sensory receptors.
Which are the main components of the CNS?
Central Nervous System
The central nervous system (CNS) consists of the brain and spinal cord.
The CNS processes many different
kinds of incoming sensory information. It is also the source of thoughts, emotions, and memories. Most nerve impulses that stimulate muscles to contract and glands to secrete originate in the CNS.
Which are the main components of the PNS and further subdivisions?
The peripheral nervous system (PNS) includes all nervous tissue outside the CNS. Components of the PNS include cranial nerves and their branches, spinal nerves and their branches, ganglia, and sensory receptors. The PNS may be subdivided further into a somatic nervous system (SNS)
(somat- body), an autonomic nervous system (ANS) (auto- self; -nomic law), and an enteric nervous system (ENS) (enter- intestines)
Give an overview of the different organizational structures of the nervous system
Nervous system
Structural Classification of Neurons
- Multipolar neurons usually have several dendrites and one axon . Most neurons in the brain and spinal cord are of this type.
- Bipolar neurons have one main dendrite and one axon. They are found in the retina of the eye, in the inner ear, and in the olfactory (olfact to smell) area of the brain.
- Unipolar neurons have dendrites and one axon that are fused together to form a continuous process that emerges
Explain the Functions of Neurons
Functions of Neurons
- Sensory or afferent neurons ( af- toward; -ferrent carried ) either contain sensory receptors at their distal ends (dendrites) or are located just after sensory receptors that are separate cells.Once an appropriate stimulus activates a sensory receptor, the sensory neuron forms an action potential in its axon and the action potential is conveyed into the CNS through cranial or spinal nerves. Most sensory neurons are unipolar in structure.
- Motor or efferent neurons ( ef- away from) convey action potentials away from the CNS to effectors (muscles and glands) in the periphery (PNS) through cranial and spinal nerves. Most motor neurons are multipolar in structure.
- Interneurons or association neurons are mainly located within the CNS between sensory and motor neurons. Interneurons integrate (process) incoming sensory information from sensory neurons and then elicit a motor response by activating the appropriate motor
Name the different types of Neuroglial Cells in CNS
Types of Neuroglial Cells in CNS
- Astrocytes
- Microglia
- Oligodendrocytes
- Ependymal cells
Name the different types of Neuroglial Cells in PNS
Types of Neuroglial Cells in PNS
- Schwann cells
- Satellite cells
Describe functions of Astrocytes
Astrocytes - Neuroglial Cell CNS
Support neurons; protect neurons from harmful substances; help maintain proper chemical environment for generation of nerve impulses; assist with growth and migration of neurons during brain development; play a role in learning and memory; help form the blood–brain barrier.
Describe functions of Microglia
Microglia - Neuroglial Cell CNS
Function: Protect CNS cells from disease by engulfing invading microbes; migrate to areas of injured nerve tissue where they clear away debris of dead cells.
Describe functions of Oligodendrocytes
Oligodendrocytes - Neuroglial Cell CNS
Function: Produce and maintain myelin sheath around several adjacent axons of CNS neurons.
Describe functions of Ependymal cells
Ependymal cells - Neuroglial Cell CNS
Functions: Line ventricles of the brain (cavities filled with cerebrospinal fluid) and central canal of the spinal cord; form cerebrospinal fluid and assist in its circulation.
Describe functions of Schwann cells
Schwann cells - Neuroglial Cell PNS
Functions: Produce and maintain myelin sheath around a single axon of a PNS neuron; participate in regeneration of PNS axons.
Describe functions of Satellite cells
Satellite cells - Neuroglial Cell PNS
Functions: Support neurons in PNS ganglia and regulate exchange of materials between neurons and interstitial fluid.
Explain Action Potential
Action Potential
Explain Conduction of Nerve Impulses
Conduction of Nerve Impulses
Give example of Connective Tissue Cells
Connective Tissue Cells
- Fibroblasts
- Macrophages
- Plasma Cells
- Mast Cells
- Adipocytes (Fat cells)
Describe Fibroblasts
Fibroblasts Connective Tissue
Fibroblasts ( fibro- fibers) are large, flat
cells with branching processes. They are present in several
connective tissues, and usually are the most numerous.
Fibroblasts migrate through the connective tissue,
secreting the fibers and ground substance of the extracellular
matrix.
Describe Macrophages
Macrophages - Connective Tissues
Macrophages ( macro- large; -phages
eaters) develop from monocytes, a type of white blood
cell. Macrophages have an irregular shape with short
branching projections and are capable of engulfing bacteria
and cellular debris by phagocytosis.
Describe Plasma Cells
Plasma Cells - Connective Tissues
Plasma cells are small cells that develop from a type of
white blood cell called a B lymphocyte. Plasma cells secrete
antibodies, proteins that attack or neutralize foreign
substances in the body. Thus, plasma cells are an important
part of the body’s immune response.
Describe Mast Cells
Mast Cells - Connective Tissue
Mast cells are abundant alongside the blood vessels that
supply connective tissue. They produce histamine, a
chemical that dilates small blood vessels as part of the inflammatory
response, the body’s reaction to injury or
infection. Mast cells can also kill bacteria.
Describe Adipocytes
Adipocytes - Connective Tissues
Adipocytes (A-di-po¯ -sı¯ts), also called fat cells or adipose
cells, are connective tissue cells that store triglycerides
(fats). They are found below the skin and around organs
such as the heart and kidneys.
Explain ECM
Connective Tissue Extracellular Matrix
Each type of connective tissue has unique properties, based
on the specific extracellular materials between the cells. The
extracellular matrix consists of a fluid, gel, or solid ground
substance plus protein fibers.
Explain Areolar Connective Tissue
Areolar Connective Tissue - Loose CT
Description: Consists of fibers (collagen, elastic, and reticular) and several kinds of cells (fibroblasts, macrophages, plasma cells, adipocytes, and mast cells) embedded in a semifluid ground substance
Location: Subcutaneous layer deep to skin; superficial region of dermis of skin; connective tissue layer of mucousmembranes; and around blood vessels, nerves, and body organs.
Function: Strength, elasticity, and support.
Explain Adipose tissue
Adipose tissue - Loose CT
Description: Consists of adipocytes, cells specialized to store triglycerides (fats) as a large centrally located droplet; nucleus and cytoplasm are peripherally located.
Location: Subcutaneous layer deep to skin, around heart and kidneys, yellow bone marrow, and padding around joints and behind eyeball in eye socket.
Function: Reduces heat loss through skin, serves as an energy reserve, supports, and protects.
Explain Dense Regular Connective Tissue
Dense Regular Connective Tissue - Dense Connective Tissue
Description: Extracellular matrix looks shiny white; consists mainly of collagen fibers regularly arranged in bundles; fibroblasts present in rows between bundles.
Location: 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).
Function: Provides strong attachment between various structures.
Explain Dense Irregular Connective Tissue
Dense Irregular Connective Tissue - Dense CT
Description: Consists predominantly of collagen fibers randomly arranged and a few fibroblasts.
Location: Fasciae (tissue beneath skin and around muscles and other organs), deeper region of dermis of skin, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs (kidneys, liver, testes, lymph nodes), pericardium of the heart, and heart valves.
Function: Provides strength.
Explain Elastic Connective Tissue
Elastic Connective Tissue - Dense CT
Description: Consists predominantly of elastic fibers; fibroblasts are present in spaces between fibers.
Location: Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspensory ligament of penis, and ligaments between vertebrae.
Function: Allows stretching of various organs.
Explain Hyaline cartilage
Hyaline cartilage - Cartilage CT
Description: Consists of a bluish-white, shiny ground substance in the body (can stain pink or purple when prepared for microscopic examination) with fine collagen fibers and many chondrocytes; most abundant type of cartilage.
Location: Ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic and fetal skeleton.
Function: Provides smooth surfaces for movement at joints, as well as flexibility and support.
Explain Fibrocartilage
Fibrocartilage - Cartilage CT
Description: Consists of chondrocytes scattered among bundles of collagen fibers within the extracellular matrix.
Location: Pubic symphysis (point where hip bones join anteriorly), intervertebral discs (discs between vertebrae), menisci (cartilage pads) of knee, and portions of tendons that insert into cartilage.
Function: Support and joining structures together.
Explain Elastic cartilage
Elastic cartilage - Cartilage
Description: Consists of chondrocytes located in a threadlike network of elastic fibers within the extracellular matrix.
Location: Lid on top of larynx (epiglottis), part of external ear (auricle), and auditory (eustachian) tubes.
Function: Gives support and maintains shape.
Explain the Functions of Blood - Liquid Connective Tissues
Functions of Liquid Connective Tissues
Blood
- Transports gases, nutrients, waste, cells, enzymes, hormones etc.
- Regulating electrolytes, pH, fluid balance, and temperature
- Coagulation
- Defense - white blood cells, antibodies
