Ch 3 lecture Tissues Flashcards
- Tissues
a. Groups of closely associated cells that perform related function and are similar in structure
- What are the four major categories of tissues
a. Epithelial
b. Connective
c. Muscle
d. Nervous
- Histology
a. The study of tissues
b. Provides the structural basis for a study of organ physiology
- What is an epithelium
a. F
- Epithelia
a. The tissues that covers the external body surface (epidermis), lines it cavities and tubules
b. “marks off our insides from our outsides.”
- Are glands epithelium?
a. Yes
b. Since glands develop from epithelial membranes they are also classed as epithelium
- What are some functions of epithelium?
a. Protection, absorption, filtration, secretion and sensory reception
- What are the unique characteristics of epithelial tissues
a. Cellularity, special contacts, polarity, supported by connective tissue, avascular but innervated, high regenerative capacity
- Cellularity
a. Composed almost entirely of cells
- Special contacts
a. Form continuous sheets held together by tight junctions and desmosomes
- Polarity
a. Apical (upper free)
b. Basal (lower attached) surfaces
- Supported by connective tissue
a. Reticular and basal laminae (basement membrane)
- Avascular but innervated
a. A
- High regenerative capacity
a. Rapidly replaces lost cells by cell division
- Epithelia are classified according to two criteria
a. Arrangement or relative number of layers (first name of tissue)
b. Cell shape (last name if tissue
- Arrangement of epithelia?
a. Simple and stratified
b. Simple
i. Consisting of one layer of cells attached to the basement membrane
c. Stratified
i. Consisting of two or more layers of cells
- Types of epithelia
simple, cuboidal, columnar
a. Squamous
i. Cells wider than tall (plate-like)
ii. Nuclei top
b. Cuboidal
i. Cells are as wide as tall (cube-like)
ii. Nuclei middle
c. Columnar
i. Cells are taller than they are wide (column-like)
ii. Nuclei bottom
- Stratified epithelia are named?
a. According to the cells at the apical surface of the epithelial membrane, not those resting on the basement membrane
- Pseudostratified epithelium
a. Simple columnar epithelium
b. Cells vary in height and nuclei lie at different levels above the basement membrane
c. Ciliated
- Transitional epithelium
a. Stratified squamous epithelium are formed of rounded, or “plump” cells with the ability to slide over one another to allow the organ to be stretched
b. Only found in urinary system organs
i. Bladder
- Simple squamous epithelium
a. A single layer of flat cells with disc shaped nuclei and sparse cytoplasm
- Function of simple squamous epithelium
a. Passage of materials by passive diffusion and filtration and secretes lubricating substances in serosae (membranes)
- Special types of simple squamous epithelium
a. Endothelium
b. Mesothelium
- Endothelium
a. Inner covering
b. Slick lining of hollow organs
- Mesothelium
a. Middle covering
b. Lines peritoneal, pleural, and pericardial cavities
c. Covers visceral organs of those cavities
- Simple squamous epithelium location
a. Renal corpuscles, alveoli of lungs, lining of heart, blood and lymphatic vessels, lining of ventral body cavity (serosae)
- Simple cuboidal epithelia
a. Single layer of cube-like cells with large, spherical central nuclei
- Functions of simple cuboidal epithelium
a. Secretion and absorption
- Location of simple cuboidal epithelial
a. Kidney tubules, secretory portion of small glands, ovary surface
- Simple columnar epithelia
a. Single layer of column-shaped (rectangular) cells witih oval nuclei
b. Some bear cilia at their apical surface
c. May contain goblet (mucus secreting) cells
- Simple columnar epithelia functions
a. Absorption
b. Secretion of mucus, ion transport, ciliated type propels mucus or reproductive cells by ciliary action
- Location of simple columnar epithelia
a. Non-ciliated form
b. Lines digestive tract, gall bladder, ducts of some glands
Ciliated form- b. Lines small bronchi, fallopian tubes, and uterus
- Pseudostratified columnar epithelial
a. All cells originate at basement membrane
b. Only tall cells reach the apical surface
c. May contain goblet cells and bear cilia
d. Nuclei lie at varying heights within cells
e. Gives false impression of stratification
- Function of pseudostratified columnar epithelial
a. Secretion of mucus
b. Propulsion of mucus by cilia
- Location of pseudostratified columnar epithelia
a. Non-ciliated form
b. Ciliated form
- Non-ciliated form of pseudostratified columnar epithelia location
a. Ducts of male reproductive tubes and ducts of large glands
- Ciliated form of pseudostratified columnar epithelia location
a. Lines trachea and most of upper respiratory tract
- Stratified squamous epithelium
a. Many layers of cells
b. Superficial layers are squamous in shape while deeper layers of cells appear cuboidal or columnar
c. Thickest epithelial tissue
d. Adapted for protection
- Function of stratified squamous epithelium
a. Protects underlying tissues in areas subject to abrasion
- Location of stratified squamous epithelium
a. Keratinized forms – epidermis
b. Non-keratinized forms
i. Lining of esophagus, mouth, and vagina
- Stratified cuboidal epithelium
a. Generally two layers of cube-shaped cells
- Function of stratified cuboidal epithelium
a. Protection
- Location of stratified cuboidal epithelium
a. Forms largest ducts of sweat glands and forms cuts of mammary glands and salivary glands
- Stratified columnar epithelium
a. Several layers
b. Basal cells usually cuboidal
c. Superficial cells elongated
- Function of stratified columnar epithelium
a. Protection and secretion
- Location of stratified columnar epithelium
a. Rarest tissue types
b. Found in male urethra and large ducts of some glands
- Transitional epithelium
a. Basal cells usually cuboidal or columnar
b. Superficial cells dome-shaped or squamous
c. Undergoes transition in shape
- Function of transitional epithelium
a. Stretches
b. Permits distention of urinary bladder causing thinning
i. From 6 to 3 layers when filled with urine
- Location of transitional epithelium
a. Lines ureters
b. Urinary bladder
c. Part of urethra
- Gland
a. Many epithelial cells that make and secrete a product
- The products of a gland are?
a. Aqueous fluids that usually contain proteins
- Epithelial cells forming glands are highly specialized to?
a. Remove materials from the blood
b. Manufacture them into new materials, which they secrete (recall RER)
- Glands are classified by?
a. Site of release: endocrine (“internally releasing”) vs. exocrine (“externally releasing”)
b. The relative number of cells forming the gland
- Endocrine glands
a. Lose their surface connection (duct) as they develop
b. Referred to as “ductless glands”
- Endocrine glands secrete hormones to?
a. Directly into the blood or the lymphatic vessels that weave through the glands to specific target organs farm from the site of release
- Exocrine glands
a. Retain their ducts, and their secretions empty through these ducts to an epithelial surface
b. Internal and external
- In addition to the site of product release, glands are also classified based upon the?
a. Relative number of cells forming the gland: unicellular and multicellular
- Unicellular
a. Scattered within epithelial sheets
- Multicellular
a. Formed by invagination or invaginations and usually have ducts that carry products of exocrine glands to epithelial surface
- Ducts
a. Tube-like connections to epithelial sheets
- Unicellular exocrine glands
a. The goblet cell
b. Scattered through epithelial lining of intestines and respiratory tubes, between columnar cells
- Goblets cells produce
a. Mucin
- Mucin
a. Glycoprotein that dissolves In H2O to become slimy
i. Mucin + water = mucus
b. Covers, protects, and lubricates many internal body surfaces
- Multicellular exocrine glands: two basic parts
a. Secretory unit
b. Epithelium-walled duct
- Multicellular exocrine glands classified by structure of duct
a. Simple (unbranched), compound (branched)
- Multicellular exocrine glands categorized by secretory unit structure
a. Tubular
b. Alveolar = acinar
c. Tubuloalveolar
- Tubular
a. Secretory cells form tubes
- Alveolar = acinar
a. Secretory cells form small flask-like sacs
- Lateral surface features: Three factors act to bind epithelial cells to one another
a. Adhesion proteins in the plasma membranes link together adjacent cells
b. The wavy contours of the membranes of adjacent cells (tongue and groove)
c. Special cell junctions
- Lateral surface features: cell junctions
a. Tight junctions (zonula occludens)
i. Belt-like junction that extends around periphery (apical region)
ii. Closes of extracellular space
iii. Some proteins in plasma membrane of adjacent cells are fused
- When proteins in plasma membrane of adjacent cells are fused it?
a. Prevents molecules from passing between cells of epithelial tissue
- Lateral surface features: cell junctions
a. Adherens junctions (zonula adherens)
i. An anchoring junction just below tight junctions
ii. Transmembrane linker proteins attach to actin microfilaments of the cytoskeleton and bind adjacent cells
- Adherens junction with tight junctions
a. Form the tight junctional complex around apical lateral borders of epithelial tissues
- Lateral surface features: cell junctions
a. Desmosomes
i. Anchoring junctions
ii. Main junctions for binding cells together
iii. Two disc-like plaques connected across intercellular space
- Desmosomes plaques of adjoining cells are joined by?
a. Proteins called cadherins
- Cadherins proteins interdigitate into?
a. Extracellular space
- Intermediate filaments of desmosomes insert into plaques from?
a. Cytoplasmic side
- Lateral surface features: cell junctions
a. Gap junctions (nexus)
i. Tunnel-like passageway between two adjacent cells (anywhere)
ii. Let small molecules move directly between neighboring cells
- Cells in gap junctions are connected by?
a. Hollow cylinders of protein (connexons)
- Basal surface feature:
a. Basal lamina
- Lateral surface features?
a. Cell junctions
- Apical surface feature?
a. Microvilli
b. Cilia
c. axoneme
- Basal lamina
a. The border between the epithelia and the underlying C.T
b. Non-cellular supporting sheet of proteins secreted by epithelial cells
- Functions of basal lamina
a. Acts as a selective filter, determining which molecules from capillaries enter the epithelium
b. Acts as scaffolding along which regenerating epithelial cells can migrate
- What forms the basement membrane?
a. Basal lamina and reticular layers of the underlying connective tissue deep to it
- Clinical application of basal lamina in Untreated cases of DM
a. Basement membrane associated with endothelium of capillaries thicken over time, probably because that take up glucose which is present in very high concentration
- Why is kidney failure and blindness are major symptoms of diabetes
a. Thickening in especially evident in capillaries of kidneys and the retina of the eyes, making them nonfunctional
- Microvilli
a. Finger like extensions of plasma membrane
b. Maximize surface area across which small molecules enter or leave
c. Abundant in epithelia of small intestine and kidney
- Apical surface features: cilia
a. Whip-like, highly motile extensions of apical surface membranes
- Apical surface features: cilia
a. Axoneme
i. Set of microtubules
ii. Contains a core of nine pairs of microtubules encircling one middle pair
iii. Each pair of microtubules arranged in a doublet
- Movement of cilia
a. Coordinated waves
- Other motile appendages: flagella
a. Flaggelum
i. Extremely long cilia used to propel cells/organisms
ii. Example: sperm cells
- Movement of flagella
a. Whip like pattern
- Connective tissue
a. Found in all parts of the body as discrete structures or as part of various body organs
- Functions of connective tissue
a. Protect, support, and bind together (tendons and ligaments) other tissues of the body
- Examples of connective tissue
a. Osseous tissue
b. Areolar connective tissue
c. Adipose (fat) tissue
d. Hematopoietic tissue
- Osseous tissue
a. Connective tissue of the bones
- Areolar connective tissue
a. Soft packaging material that cushions and protects body organs
- Adipose (fat) tissue
a. Provides insulation of the body tissues and a source of stored food
- Hematopoietic tissue
a. Replenished the body’s supply of red blood cells
- What are the four main types of connective tissue?
a. Connective tissue proper
b. Cartilage
c. Bone tissue
d. Blood
- Connective tissue proper
a. Fat tissue and fibrous tissue of ligaments
- Does all connective tissues share the same simple structural plan?
a. Yes
- All types of Connective Tissues originate from the?
a. Embryonic tissue called mesenchyme
- Connective tissue proper organization from mesenchyme
a. Mesenchyme -> fibroblast -> fibrocyte -> connective tissue proper
- Subclasses of connective tissue proper
a. Loose connective tissue and dense connective tissue
- Loose connective tissue types
a. Areolar
b. Adipose
c. Reticular
- Dense connective tissue types
a. Regular
b. Irregular
c. Elastic
- Cartilage organization from mesenchyme
a. Chondroblast -> chondrocyte -> cartilage
- Subclasses of cartilage
a. Hyaline cartilage
b. Fibrocartilage
c. Elastic cartilage
- Osseous bone tissue organization from mesenchyme
a. Mesenchyme -> osteoblast -> osteocyte -> osseous (bone)
- Subclasses of osseous (bone)
a. Compact bone
b. Spongy (cancellous) bone
- Blood tissue organization from mesenchyme
a. Mesenchyme -> hematopoietic stem cell -> blood cells (and macrophages) -> blood
- Subclasses of blood
a. Blood cell formation and differentiation are quite complex
- Characteristics of connective tissue
a. Generally have a rich supply of blood vessels
i. Exceptions: cartilage, tendons, and ligaments
- Are connective tissues are composed of many cell types?
a. Yes
- In between the cells of connective tissue are a vast amount of?
a. Noncellular (non-living material), called the extracellular matrix
- The extracellular matrix distinguishes?
a. Connective tissue from all other tissues
- The extracellular matrix
a. Produced by the cells and then extruded
b. Accounts for the strength of connective tissue but?
- The matrix has two structural components
a. Ground substance
b. Fibers
- Ground substance of matrix functions as
a. Medium through which nutrients and other dissolved substances can diffuse between the blood capillaries and cells
b. Holds the interstitial fluid
- Fibers
a. Provide support
b. All made from a single cell called the fibroblast
- Examples of fibers
a. Collagen, fibers, elastic fibers, and reticular fibers
- The differences between the physical properties and functiosn of each type of connective tissue are due to?
a. Differences in the composition of the extracellular matrix
- Connective tissue proper general features
a. Six different types
b. Vary in density and types of fibers
c. Function as a binding tissue
d. Resists mechanical stress
e. Particularly tension
- Cartilage general features
a. Resists compression because of the large amounts of water held in the matrix
b. Functions to cushion and support body structures
- Bone tissue general features
a. Hard tissue that resists both compression and tension
b. Functions in support
- Blood general features
a. A fluid tissue
b. Functions to carry O2, CO2, nutrients, wastes, and other substances (hormones, for example)
- Areolar connective tissue
a. Underlies almost all the epithelia of the body and surrounds almost all the small nerves and blood vessels
- Basic functions of areolar connective tissues
a. Support and binding of other tissues
b. Holding body fluids
c. Defending the body against infections
d. Storing nutrients as fat
- Collagen fibers
a. Strongest and most abundant type
b. Allow connective tissue to withstand tension
c. Cross-linking of collagen fibers gives collagen its strength
- Fibers provide support
a. Collagen
b. Reticular
c. Elastic
- Reticular fibers
a. Bundles of special type of collagen
- Reticular fibers cluster into?
a. Networks (reticulum) that cover and support all structures bordering the CT
b. E.g surrounds capillaries and borders nearby epithelia
- When pulled reticular fibers Fibers glide freely past one another and allow more give, therefore?
a. Capillaries are not choked by the surrounding reticular fibers when they expand
- Elastic fibers
a. Long and thing
b. Form wide networks within the ECM
c. Made up of collagen but also contain elastin, which allows them to function like rubber bands
- Ground substance of elastic fibers
a. The part of the extracellular matrix that holds the tissue fluid Derived from the blood
- Ground substance of elastic fibers consists of?
a. large sugar (glycoaminoglycans) and sugar protein molecules (proteoglycans) that soak up fluid like a sponge
- ground substance of elastic fibers functions as a?
a. medium through which nutrients, wastes and other dissolved substances can diffuse between the blood capillaries and cells
- Areolar CT
a. Site of body’s war against infectious microorganisms
i. Bacteria, viruses, fungi, and parasites
- Areolar CT contains a variety of?
a. Defense cells all of which originate as blood cells and migrate to the connective tissue by leaving the capillaries
- What cells of areolar CT work to defend the body
a. Macrophages
b. Plasma cells
c. Mast cells
d. Neutrophils, lymphocytes, eosinophils
- Areolar CT also stores energy reserves as?
a. Fat
b. Cannot divide
- The large, fat-storing cells are called?
a. Fat cells
b. Adipose or adipocytes
- The cytoplasm of adipocytes is dominated by?
a. Single, giant lipid droplet that flattens the nucleus and cytoplasm at one end of the cell
- Connective tissue proper 2 subclasses
a. Loose connective tissue (more cells/less matrix)
b. Dense (fibrous) connective tissue (less cells/more matrix)
- Loose connective tissue
a. Areolar ct
b. Adipose ct
c. Reticular ct
- Areolar
a. Gel-like matrix with all three fiber types cells: fibroblasts, macrophages, mast cells, and some white blood cells
- Areolar functions
a. Wraps and cushions organs
b. Macrophages phagocytize bacteria
c. Plays important role inflammation
d. Holds and conveys tissue fluid
- Location of areolar ct
a. Widely distributed under epithelia of body
b. Eg. Forms lamina propria of mucous membranes
c. Packages organs
d. Surrounds capillaries
- Adipose connective tissue
a. 90% of mass consists of fat cells
b. Highly vascularized
c. Removes lipids from the bloodstream after meals and later releases them into the blood as needed
- Adipose connective tissue occurs in the?
a. Hypodermis (layer beneath the skin)
b. Mesenteries (sheets of serous membranes that hold the stomach and intestines in place)
- Description of adipose
a. Matrix is in areolar, but very sparse
b. Closely packed adipocytes, or fat cells
c. Have nucleus pushed to the side by large fat droplet
- Function of adipose
a. Provides reserve food fuel
b. Insulates against heat loss
c. Supports and protects organs
- Location of adipose
a. Under skin
b. Around kidneys and eyeballs
c. Within abdomen
d. In breasts
- Reticular connective tissue
a. Resembles areolar tissue, but the only fibers present in its matrix are reticular fibers which hold many free cells
- Reticular connective tissue found in?
a. Bone marrow, spleen, and lymph nodes (all have many free blood cells outside their capillaries)
- Description of reticular ct
a. Network or reticular fibers in a typical loose ground substance
b. Lie on the network
- Function of reticular ct
a. Fibers form a soft internal skeleton (stroma) that supports other cell types including while blood cells, mast cells, and macrophages
- Location of reticular ct
a. Lymphoid organs (lymph nodes, bone marrow, and spleen)
- Connective Tissue: Dense type
a. Regular ct
b. Irregular ct
- Dense irregular connective tissue
a. Resembles areolar tissue, but the collagen fibers are much thicker
- What allows dense irregular CT to resist tensions from different directions?
a. Collagen fibers that run in different planes
- Dense Irregular ct description
a. Primarily irregularly arranged collagen fibers
b. Some elastic fibers
c. Major cell type is the fibroblast
- Functions of dense irregular ct
a. Able to withstand tension exerted in many directions
b. Provides structural strength
- Location of dense irregular ct
a. Dermis of the skin
b. Submucosa of digestive tract
c. Fibrous capsules of organs and of joints
- Dense regular connective tissue
a. Collagen fibers run in the same direction…parallel to the direction of pull
b. Crowded between the fibers are rows of fibroblasts
c. Poorly vascularized, no fat or defense cells
- Fibroblasts of dense regular ct
a. Continuously produce the collagen fibers and scant ground substance
- Description of dense regular ct
a. Primarily parallel collagen fibers
b. Few elastin fibers
c. Major cell type is the fibroblast
- Functions of dense regular ct
a. Attaches muscles to bones or to muscle
b. Attaches bones to bones
c. Withstands great tensile stress when pulling force is applied in one direction
- Location of dense regular ct
a. Tendons, most ligaments, aponeuroses
- Dense (regular) elastic connective tissue
a. In a few ligaments, bundles of elastic fibers outnumber the collagen fibers
- Example of dense regular elastic ct
a. Ligamentum flavum
- Connective tissue: cartilage
a. A firm connective tissue resist compression (pressing) as well as tension
- Cartilage matrix
a. Thin collagen, ground substance, lots of tissue fluid
b. Cartilage consists of 80% water
- Cartilage is a firm, flexible tissue that contains no blood vessels or nerves and just one kind of cell called?
a. Chondrocyte
- Chondrocyte is contained within a cavity called
a. Lacuna
- Immature chondrocytes are called
a. Chondroblasts which secrete the matrix during cartilage growth
- 3 types of cartilage
a. Hyaline cartilage
b. Fibrocartilage
c. Elastic cartilage
- Hyaline (glassy) description
a. Amorphous but firm matrix
b. Collagen fibers form an imperceptible network
c. Chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae
- Function of hyaline
a. Supports and reinforces
b. Has resilient cushioning properties
c. Resists compressive stress
- Location of hyaline
a. Forms most of the embryonic skeleton
b. Covers the ends of long bones in join cavities
c. Forms costal cartilages of the ribs
d. Cartilages of the nose, trachea and larynx
- Fibrocartilage description
a. Matrix similar to but less firm than that in hyaline cartilage
b. Thick collagen fibers predominate
c. Function of fibrocartilage
d. Tensile strength with the ability to absorb compressive shock
- Fibrocartilage function
a. Tensile strength with the ability to absorb compressive shock
- Location of fibrocartilage
a. Intervertebral discs
b. Pubic symphysis
c. Discs of knee joint
- Elastic cartilage description
a. Similar to hyaline cartilage, but more elastic fibers in matrix
- Function of elastic
a. Maintains the shape of a structure while allowing great flexibility
- Location of elastic cartilage
a. Supports the external ear (pinna)
b. Epiglottis
- Bone (Osseous) tissue characteristics
a. Calcified matrix containing many collagen fibers
b. Osteoblasts (immature)
c. Osteocytes
d. Very well vascularized
- Osteoblasts
a. Immature
b. Secrete collagen fibers and matrix
- Osteocytes
a. Mature bone cells in lacunae
- Functions of bone osseous tissue
a. Supports and protects organs
b. Provides levers and attachment sites for muscles
c. Stores calcium, fat and mineral
- Bone marrow is site for?
a. Blood formation
- Bone description
a. Hard, calcified matrix containing many collagen fibers
b. Osteocytes lie in lacuna
c. Very well vascularized
- Blood tissue
a. The fluid in the blood vessels
- Why is blood tissue the most atypical connective tissue?
a. It does not bind things together or give mechanical support
- Why is blood classified as connective tissue?
a. Develops from mesenchyme
b. Consists of blood cells surrounded by a nonliving matrix (plasma)
- Blood functions as a?
a. Transport vehicle for the cardiovascular system, carrying nutrients, wastes, respiratory gases, and other substances throughout the body
- Blood ct description
a. Red and white blood cells in a fluid matrix (plasma)
- Function of blood ct
a. Transport of respiratory gases, nutrients, wastes and other substances
- Location of blood ct
a. Contained within blood vessels
- Covering and lining membranes
a. Combination of epithelial and connective tissues
b. Covers broad areas within the body
- Covering and lining membranes consist of?
a. Epithelial sheet plus the underlying layer of connective tissue proper
- Three types of covering and lining membranes
a. Cutaneous
b. Mucous
c. Serous membranes
- Cutaneous membrane
a. Skin covering the outer surface of the body
i. Epithelium: the thick epidermis
ii. Connective tissue proper: the dense dermis
- Mucous membrane (mucose)
a. Lines the inside of every hollow internal organ that opens outside the body
b. Lines the tubes of the respiratory, digestive, reproductive, and urinary systems
c. All are wet and moist (many not all secrete mucus)
- All mucous membranes are consists of?
a. Epithelial sheet directly above a layer of loose connective tissue called lamina propria
- Serous membranes (serosa)
a. The slippery membranes that line the closed pleural, pericardial, and peritoneal cavities
b. Produces a slippery serous fluid
- Serous membranes all consists of a layer of?
a. Simple squamous epithelium lying on a thin layer of areolar connective tissue
- Muscle tissue
a. Brings about most kinds of body movements
- Must muscle cells are called
a. Muscle fibers because they have elongated shape and contract forcefully as they shorten
- Muscle tissue contains
a. Myofilaments – combination of actin and myosin
- Three kinds of muscle tissue
a. Skeletal
b. Cardiac
c. Smooth
- Skeletal muscle
a. Pull on bones to cause body movements
b. Long, large cylinders that contain many nuclei
- Skeletal muscle appear striated due to?
a. The organization of myofilaments
- Skeletal muscle description
a. Long, cylindrical, multinucleate cells
b. Obvious striations
- Function of skeletal muscle
a. Voluntary movement
b. Locomotion
c. Manipulation of the environment
d. Facial expression
e. Voluntary control
- Location of skeletal muscle
a. In skeletal muscles attached to bones or occasionally to skin
- Cardiac muscle
a. Occurs in the wall of the heart
b. striated
- Cardiac muscle contract to
a. Propel blood through the blood vessels
- Cells of cardiac muscle
a. Each has just one nucleus
b. Cardiac cells branch and join at special cellular junctions called intercalated discs
- Smooth muscle
a. No visible striations in its cells
b. Spindle shaped and contain one centrally located nucleus
- Smooth muscle is found in?
a. The hollow walls of vicera
b. Digestive and urinary organs, uterus and blood vessels
- Smooth muscle acts to?
a. Squeeze substance through these organs
- Smooth muscle description
a. Spindle-shaped cells with central nuclei
b. No striations
c. Cells arranged closely to form sheets
- Smooth muscles function
a. Propels substances or objects (foodstuffs, urine, a baby) along internal passageways
b. Involuntary control
- Location of smooth muscles
a. Mostly in the walls of hollow organs
- Nervous tissue main component of?
a. The nervous organs
b. The brain, spinal cord and nerves
- Nervous tissue
a. Regulate and control body functions
- Contains two types of cells:
a. Neurons
b. Supporting cells
- Neurons
a. Highly specialized cells that generate and conduct electrical impulses
b. Have extensions that allow them transmit impulses over great distances within the body
- Supporting cells
a. Non conducting cells that nourish, insulate, and protect the delicate neutrons
- Description of neurons
a. Branching cells
b. Cell processes that may be quite long extend from the nucleus containing cell body
c. Contributing to nervous tissue are nonirritable supporting cells
- Functions of neurons
a. Transmit electrical signals from sensory receptors and to effectors (muscles and glands) that control their activity
- Location of neurons
a. Brain, spinal cord, and nerves
- Tubuloalveolar
a. Secretory cells form tubular and alveolar units