cells & tissues anatomy & physiology chapter. cellular membrane & transport
TRANSCRIPT
Cells & Tissues
Anatomy & PhysiologyChapter
Cellular Membrane & Transport
Introduction:A. The human body consists of 75 trillion cells that vary considerably in shape and size yet have much in common.B. Differences in cell shape make different functions possible.
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Cell Structure: A cell consists of three main parts---
the nucleus, the cytoplasm, and the cell membrane.
Within the cytoplasm are specialized organelles that perform specific functions for the cell.
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Inside the cell: Cytoplasm The cytoplasm consists of a clear liquid
(cytosol), a supportive cytoskeleton, and networks of membranesand organelles
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Inside the cell: Cell Nucleus: large organelle bounded by a double-layered
nuclear membrane—also selectively permeable The site of cellular control Holds genetic information—DNA & RNA Contains the nucleolus
composed of RNA and protein and is the site of ribosome production
Contains chromatin loosely coiled fibers of protein and DNA
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Cell Nucleus
Inside the cell: Ribosomes Found attached to rough ER or scattered
throughout the cytoplasm Composed of protein and RNA Functions in protein synthesis
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Inside the cell: Endoplasmic Reticulum (ER) made up of membranes, flattened sacs, & vesicles provides a tubular transport system inside
the cell Rough ER: ER + ribosomes functions in
protein synthesis Smooth ER: ER without ribosomes functions
in lipid synthesis
Rough ER & Smooth ER
Inside the cell: Golgi Apparatus (GA)
composed of flattened sacs, and refines, packages, modifies, & delivers proteins
vesicles formed on ER travel to the GA GA modifies vesicles contents chemically-
prepares them for transport out of cell Vesicles form a “delivery service”, carrying chemicals
throughout the cell (vesicle trafficking).
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Protein Synthesis and Transport
Inside the cell: Mitochondria the “powerhouses” of the cell contain enzymes needed for aerobic respiration the inner membrane of the mitochondrion is
folded into cristae which hold the enzymes needed in
energy transformations to make ATP (energy used by body)
Very active cells contain thousands of mitochondria
example: skeletal muscle
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Mitochondria
Inside the cell: Lysosomes & Peroxisomes
Lysosomes are the "garbage disposals" of the cell & contain digestive enzymes to break up old cell components and bacteria
Peroxisomes contain enzymes that function in the synthesis of bile acids, breakdown of lipids, degradation of rare biochemicals, and detoxification of alcohol
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Cell Extensions Cilia and flagella are motile extensions from the
cell shorter cilia are abundant on the free surfaces of
certain epithelial cells (example: respiratory linings) a lengthy flagellum can be found on sperm cells
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Cilia Flagellum
Cellular Membrane
Separates cell contents from the surrounding environment
Very DYNAMIC in many cellular activities
What is meant by the term dynamic?
Active, participates in cellular functions
Plasma Membrane Structure
Bimolecular lipid layer contains:1. Proteins2. Glycoproteins3. Cholesterol
Plasma Membrane Structure: Proteins
Functions: Act as receptors (binding sites) for
hormones (chemical messengers) Aid in transport of materials through
membrane Pores for transport of water or water-
soluble substances Act as carriers by binding to
substances and carrying them through lipid bilayer
Plasma Membrane Structure: Glycoproteins
Sugar clusters attached to proteins Function:
Determines blood types Receptors for bacteria, viruses or
toxins
Plasma Membrane Structure: Cholesterol
Stabilizes membrane and keeps it fluid
Cell Physiology
Cells perform METABOLISM What is metabolism?
the use of nutrients to build new materials the break down of substances make ATP digest foods dispose of waste reproduce grow, move & respond to stimuli
Membrane Transport Definitions
Solution: a homogenous mixture of 2+ components Ex: air (mixture of gases), seawater
(salt, water and gases) Solvent: the substance presenting
the largest amount within the solution Ex: water = bodies major solvent
Membrane Transport Definitions
Solutes: substance present in smaller amounts within a solution Ex: oxygen in the atmosphere
Intracellular Fluid: a solution within cells; containing small amounts of gases, nutrients and salts—all dissolved in water
Membrane Transport Definitions
Interstitial or intercellular Fluid: fluid surrounding outside of cells, very nutritious contains: Hormones Salts Waste products Sugars Vitamins Etc
Selective Permeability: when a barrier allows only SOME select substances through, wither inside or outside of the cell
Membrane Transport Definitions
Passive Transport: substances are passed across the membrane without expending energy
GREAT FOR ENERGY EFFICIENCY!!
Active Transport: when a cell uses ATP to move substances across a membrane; substances are: Too large Unable to dissolve in
fat core Moving against
concentration gradient
Membrane Transport Definitions
Isotonic Solutions: has the same solute and water concentrations as cells do
Hypertonic Solutions: contains more dissolved substances than the inside of a cell
Hypotonic Solutions: contains less dissolved substances than the inside of a cell
Histology: the study of tissues
Histology SlidesCourtesy of
The JayDoc HistoWebhttp://www.kumc.edu/instruction/medicine/anatomy/
histoweb/index.htm
Definitions
Avascular: lacking a blood supply Innervated: supplied with nerves
4 Tissue Types: names and functions
1. Epithelial Tissue: protects, secretes, absorbs and forms boundaries
2. Connective Tissue: supports and protects
3. Muscular: contracts4. Nervous: transmits impulses
Epithelial Tissue: Special Characteristics
Avascular Innervated Basement membrane: acts to reinforce
the epithelial sheet, attaches to underlying connective tissue
Cells fit closely; forms continuous sheets Apical surface: free surface exposed to
exterior or to cavity of internal organs Regenerates quickly with sufficient
nourishment
Epithelial Tissue: Classification
By cell shape By number of layers
Cell Shapes Squamous: flattened cells Cuboidal: boxlike cells Columnar: higher than wide (tall)
Epithelial Tissue: Classification
Number of layers Simple: one layer Stratified: several layers Pseudostatified: single layer but
looks like two layers Transitional: several layers of cells of
different shapes
Epithelial Tissue Types
Simple Epithelia Simple squamos
epithelium Simple cuboidal
epithelium Simple columnar
epithelium Pseudostratified
epithelium
Stratified Epithelia Stratified squamos
epithelium Stratified cuboidal and
stratified columnar Transitional epithelia
Glandular Epithelium Endocrine glands Exocrine glands
1. Simple Squamous Epithelium made up of a single layer of thin,
flattened cells suited for diffusion functions in the exchange of
gases in the lungs lines blood, lymph vessels & body
cavities
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Simple Squamos Epithelium
2. Simple Cuboidal Epithelium
consists of a single layer of cube-shaped cells with centrally located nuclei
functions in secretion and absorption in the kidneys, and glands
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Simple Cuboidal Epithelium
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3. Simple Columnar Epithelium made up of a row of elongated cells
whose nuclei are all located near thebasement membrane
may be ciliated lines the uterus, stomach, and
intestines protects underlying tissues, secretes
digestive fluids, and absorbs nutrients.
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Simple Columnar Epithelium
4. Pseudostratified Columnar Epithelium
cells appear layered due to thevarying positions of their nuclei within
NOT truly layered cilia may be present associated with goblet cells, that secrete
mucus line and sweep debris from respiratory
tubes
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Psuedostratified Epithelium
Psuedostratified Epithelium
5. Stratified Squamous Epithelium
made up of layers of flattened cells designed to protect underlying layers makes up the outer layer of skin,
lines the mouth, throat, vagina, andanal canal
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6. Stratified Cuboidal Epithelium consists of 2-3 layers of cuboidal cells lines the lumen of the mammary
glands, sweat glands, salivary glands, and the pancreas
**Several layers of cells provide greaterprotection than one single layer
STRUCTURE PERTAINS TO FUNCTION
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Stratified Cuboidal
7. Stratified Columnar Epithelium consists of several layers of cells found in the vas deferens, male
urethra, & the pharynx
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8. Transitional Epithelium designed to distend and return to its
normalsize
lines the urinary bladder this design provides distensibility and
keepsurine from diffusing back into the internalcavity
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Unstretched Transitional Epithelium
Stretched Transitional Epithelium
9. Glandular Epithelium made up of cells designed to
produce andsecrete substances into ducts or into bodyfluids
Exocrine Glands: secrete products into ducts
Endocrine Glands: secrete products into blood
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Connective Tissue: Special Characteristics
Living cells surrounded by a matrix Some vascularized, others not Vary in rigidity: solid --- liquid
Types of Connective Tissues
Areolar Tissue Adipose Tissue Dense Connective
Tissue
Cartilage Hyaline cartilage Elastic cartilage Fibrocartilage
Bone Blood
Major Connective Tissue Cell TypesA. Fibroblasts: the most common cell typea large, fixed, star-shaped cell; secretesfibersB. Macrophages: wanderers, function as scavenger cells; defend against infectionC. Mast cells: large and located near
bloodvessels; release heparin (anticoagulant)and histamine (promotes inflammation).
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1. Areolar Tissue: loose connectivetissue forms delicate, thin membranes
throughout the body binds body parts together Example: skin and underlying organs majority of the cells are
fibroblasts separated by a gel-like groundsubstance that contains collagenous (tough) and elastic fibers (stretchy)
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Areolar Tissue
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2. Adipose Tissue loose connective tissue designed to store fat found beneath the skin, around joints,
padding the kidneys and other internal organs
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3. Dense Connective Tissue consists of densely packed
collagenous fibers very strong relatively avascular found as part of tendons and ligaments
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Dense Connective Tissue
4. Cartilage rigid connective tissue; provides a
supportive framework for various structures
avascular; heals slowly chondrocytes: cartilage cells 3 types:A. Hyaline cartilage: white with abundant
fine collagen fibers; found at the ends of bones;
supports respiratory passages
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B. Elastic cartilage: with elastic fibers;provides a framework for the external ears
andparts of the larynx
C. Fibrocartilage: with many collagenousfibers; a tough tissue; provides a shockabsorbing function in intervertebral disks and
in the knees & pelvic girdle
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Hyaline Cartilage
5. Bone the most rigid connective tissue, holds deposits of mineral salts and
collagen within the matrix bone internally supports the body,
protects, forms muscle attachments, and is the site for blood cell formation
Osteocytes: bone cells Highly vascularized-heals well
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Bone
6. Blood composed of cells suspended in a
liquid matrix calledplasma
functions to transport substances throughout the body
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Muscle Tissue: Special Characteristics
Highly cellular Well vascularized Muscle cell=muscle fiber
Muscle Tissue Types
1. Skeletal Muscle2. Cardiac Muscle3. Smooth Muscle
1. Skeletal Muscle Tissue attached to bone Voluntary: controlled by conscious
effort the cells are long and cylindrical,
striated, have many nuclei
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2. Smooth Muscle Tissue lacks striations, is uni-nucleate, and
consists of spindle-shaped cells involuntary muscle: controlled
subconsciously found in the walls of internal organs,
and in the digestive tract, blood vessels, and urinary bladder
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Smooth Muscle
3. Cardiac Muscle Tissue found only in the heart consists of branching fibers that are connected to each other with intercalated
disksinvoluntary muscle has a single nucleus in
eachcell but appears striated
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Cardiac Muscle
Nervous Tissues: Nervous tissues are found in the
brain,spinal cord, and nerves
Neurons, or nerve cells, conduct
nervous impulses while helper cells, orneuroglia, support and nourish the neurons
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Tissue Repair: occurs in phases
Phase 1 Inflammation: a local response to cellular injury marked by: Redness Heat Pain Swelling Loss of function
Designed to protect, localize and rid body of injurious agents
Tissue Repair: occurs in phases
Phase 2 Regeneration: replacement of destroyed tissue with same kind of tissue (48 hours- 6 weeks)
Phase 3 Fibrosis: proliferation of fibrous connective tissue (scar tissue) Fibers deposit randomly (48 hours – 6
weeks) Scar tissue is strong but inflexible and
cannot perform normal tissue tasks
Tissue Repair: occurs in phases
**Whether tissue regenerates or scar tissue forms is dependant on severity of injury and the type of tissue damaged
Phase 4 Remodeling/Maturation: the realignment of fibers (3 months to 2 years)