Download Digestive System and Body Metabolism Notes – Ch 14

Name_______________________________
Chapter 3 – Cells and Tissues
Cells - Basis of Life
 Highly organized
 Made of four primary elements – ___, ___, ___, ___
 About 60% ________
 Bathed in a dilute saltwater solution (something like seawater) called ___________ fluid
 Vary in shape and function
Anatomy of a Cell
• Cells are not all the same
• All cells share general structures
• Cells are organized into three main regions:
• _________________
• _________________
• _________________
The Nucleus
• Control center of the cell
• Contains genetic material (_______)
• Three regions:
• __________________
• __________________
• __________________
Nuclear Membrane
• Double-layered barrier of nucleus
• Contain nuclear _______ that allow for _____________ of material with the rest of the cell
Nucleolus
• Sites of ___________ _______________
• Ribosomes then migrate to the cytoplasm through nuclear pores
• Nucleus contains one or more nucleoli
Chromatin
• Genetic information in unwound form
• Composed of DNA and protein
• Scattered throughout the nucleus
• Chromatin condenses to form _______________ when the cell divides
Cytoplasm
• Material outside the nucleus and inside the plasma membrane:
• _____________
• Fluid that suspends other structures
• _____________
• Metabolic machinery of the cell
• _____________
• Non-functioning units; stored nutrients or cell products (i.e. fat droplets,
pigments, glycogen, mucus)
Cytoplasmic Organelles:
Ribosomes
• Sites of ___________ synthesis
• Made of protein and RNA
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Found in two locations:
• Free in the cytoplasm
• Attached to _________ endoplasmic reticulum
• ‘Factory Worker’
Endoplasmic Reticulum
• Fluid-filled tubules for carrying substances
• Two types of ER
• Rough ER:
• Site where proteins of cellular membrane are _________ and ______________
• Studded with ribosomes (makes it look ‘rough’)
• ‘Factory that houses the factory workers’
• Smooth ER:
• Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of
drugs
• No ribosomes
Golgi Apparatus
• ____________ and _____________ proteins from rough ER
• Produces different types of packages:
• Secretory vesicles
• Cell membrane components
• Lysosomes
• ‘Stack of flattened sacs’
• ‘FedEx Shipping Plant’
Lysosomes and Peroxisomes
• Lysosomes:
• Contain _____________ that digest materials within the cell
• Used in programmed cell death
• Peroxisomes:
• _____________ harmful substances
• Break down free radicals (highly reactive, dangerous chemicals) to H2O2, then to water
and O2
• Membranous sacs of special enzymes (like catalase)
• Replicate by pinching in half
Mitochondria
• Carry out reactions where oxygen is used to break down food
• Provides _______ for cellular energy
• Change shape continuously
• ‘Mighty Mitochondria’
• ‘Powerhouse of the cell’
Cytoskelton
• Provides the cell with an internal _______________
• Network of protein structures that extend throughout the cytoplasm
• ‘Scaffold of the cell’
• Three different types:
• _______________-cell motility and change in shape- actin and myosin
• _______________ filaments-form desmosomes and internal guy wires-fibrous subunits
• _______________-determine shape of cell-tubulin subunits
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Name_______________________________
Centrioles
• Site for formation of mitotic ______________ during cell division
• Able to form _______ and ____________ in special cells
• Rod-shaped bodies made of microtubules
• Arranged in a 9+3 formation
Cell Diversity
• 75 to 100 trillion cells in human body
• 200 different cell types
• 1. ______________________________
• Fibroblast
• Erythrocyte (RBCs)
• 2. ____________________________________
• Epithelial Cell
• 3. _____________________________________
• Skeletal muscle
• Smooth muscle
• 4. ____________________________
• Fat cell
• 5. ____________________________
• Macrophage cell
• 6. _____________________________________
• Nerve cell
• 7. ____________________________
• Ovum (egg)
• Sperm
Plasma Membrane
____________ ____________ Components of the Cell
• _______________ bilayer - two lipid (fat) layers arranged “tail to tail”; hydrophilic “heads” and
hydrophobic “tails”
• _______________ - integral and peripheral; may be enzymes, receptors for hormones, involved
in cell recognition, cell adhesion, cytoskeleton attachment, transport, or generating action
potentials
• _______________ - gives stability to membrane
• _______________ - “sugar coating”; glycoproteins, glycolipids; “self” recognition, determine
blood type, immunity to infection, cancer defense, cell-to-cell interactions, guides embryonic
cells
Specializations of the Plasma Membrane
• ________________ - tiny finger-like projections that increase surface area (absorption in small
intestine)
• Membrane ________________
Membrane Junctions
• __________ junction – impermeable, “leakproof” fusion of plasma membranes; i.e. between
small intestine
• _____________ – anchoring “buttonlike” junction, prevents cells from being pulled apart; i.e.
between skin cells
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Name_______________________________
________ junction – a channel of connexons that allows chemical substances to pass between
cells; i.e. in heart and embryonic cells
Cell Physiology
Membrane Transport
Passive Membrane Transport
• Driven by kinetic energy of solutes, _____ _______ required
• ______________
• Facilitated diffusion
• Osmosis
• Lipid soluble =substances dissolve in lipids
• Water soluble =substances dissolve in water
• Water soluble substances will not dissolve in lipids and vise-versa
• Solute - what is being dissolved
• Solvent - what is doing the dissolving
Diffusion
• Particles move from an area of ______ concentration to an area of _____ concentration (or down
their concentration _____________)
• Particles diffuse directly through the plasma membrane
• Lipid-soluble
• Some must diffuse through channel proteins
• Lipid-insoluble
• Facilitated diffusion – large, polar molecules such as simple sugars
• Combine with protein carriers (channel proteins)
• Diffusion of water across a semipermeable membrane
• Osmolarity – total concentration of solute particles in a solution
Tonicity
• ______________ – solutions with the same solute concentration as that of the cytosol
•
______________ – solutions having greater solute concentration than that of the cytosol
•
______________ – solutions having lesser solute concentration than that of the cytosol
Active Transport
• Uses ATP to move solutes across a membrane ____________ its concentration gradient
• Requires carrier proteins
• Solute Pumping
• Example: Sodium-Potassium Pump - 3 Na+ out, 2 K- in; phosphorylation opens pump to
outside; dephosphorylation opens pump to inside
Vesicular Transport:
• Transport of large particles and macromolecules across plasma membranes
• Two types:
• Exocytosis - “out of the cell”
• Endocytosis - “into the cell”
• 3 types of endocytosis:
• (1) ____________ “cell eating”– pseudopods engulf solids and bring them into the cell’s interior
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Name_______________________________
(2) _______________ endocytosis (formerly pinocytosis “cell drinking”)– the plasma membrane
infolds, bringing extracellular fluid and solutes into the interior of the cell
(3) ___________________ endocytosis – uses clathrin-coated pits (clathrin is a protein) for
specific uptake of macromolecules
Examples in Human Body
• _________________
• An abnormally low concentration of sodium in the blood. Too little sodium can cause
cells to malfunction, and can be fatal.
Symptoms: abnormal mental status, brain
swelling, convulsions, headache, nausea, muscle spasms or cramps Causes: burns,
diarrhea, diuretics, kidney disease, sweating, vomiting, drinking too much water
• _________________
• a potent neurotoxin with no known antidote (pufferfish, porcupine fish, ocean sunfish,
triggerfish) blocks action potentials in nerves by binding to sodium channels in nerve
cell membranes, preventing any affected nerve cells from firing; paralysis and death
within 20 min to 8 hours after ingestion.
Cell Division
Cell Life Cycle
• Cells have two major periods:
• _____________
• Cell grows
• Cell carries on metabolic processes
• Cell replicates DNA
• _________________
• Cell replicates itself
• Function is to produce more cells for growth and repair processes
DNA Replication
• Genetic material duplicated and readies a cell for division into two cells
• Occurs toward the end of _______________
• DNA uncoils and each side serves as a template
Events of Cell Division
• ___________
• Division of the nucleus
• Results in the formation of two daughter nuclei
• Cytokinesis
• Division of the cytoplasm
• Begins when mitosis is near completion
• Results in the formation of two daughter cells
Interphase
• No cell division occurs
• The cell carries out normal metabolic activity and growth; transcription (DNA to mRNA),
translation (mRNA to proteins), organelles duplicate
• Three stages:
• ___ - cell grows and functions normally
• ___ - (Synthesis) - DNA is duplicated
• ___ cell resumes growth
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Name_______________________________
Stages of Mitosis
• “A guy named Pro Met-a girl named Ana, and they Telo-phoned each other.”
• ___________
• Nuclear envelope begins to dissolve
• Centrioles migrate to the poles
• Chromatin starts to bundle into chromosomes (two chromatids)
• The familiar ‘X’ shape
• _____________
• Chromosomes align at the center of the cell
• Special microtubules called spindle fibers attach to the chromosome’s centromeres
• _____________
• Spindle fibers shorten and duplicated chromosomes (chromatids) are pulled toward the
poles
• The cell begins to elongate
• ____________
• Chromosomes uncoil to become chromatin again
• Nuclear envelope forms around each chromatin mass
• A cleavage furrow (for cell division) begins to form
_______________
• Cytoplasm pinches into two parts
• Two smaller daughter cells that are genetically identical are the result
Protein Synthesis
In addition to replicating itself during cell division, DNA serves as the master blueprint for
___________ synthesis.
List some examples of proteins in the body:
Two major phases of protein synthesis:
_________________
• Involves the transfer of information from the DNA molecule into the complementary base
sequence of mRNA in the nucleus.
_________________
• The “language” of the nucleic acids (base sequence) is “translated” into the language of proteins
(amino acid sequence) on ribosomes in the cytoplasm.
Body Tissues
Tissues - groups of cells that are similar in structure and function
Four tissue types and general function:
EPITHELIUM - covering
CONNECTIVE - support
MUSCLE - movement
NERVOUS - control
Epithelial Tissue (Epithelium)
• the lining, covering, and glandular tissue of the body
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Name_______________________________
• protection (skin, respiratory tract), absorption (stomach, small intestine), filtration (kidneys), and
secretion (glands-sweat, oil, digestive enzymes, mucus)
Special Characteristics of Epithelium
• form continuous sheets, joined by desmosomes and tight junctions
• apical surface= free surface or edge exposed to body’s exterior or cavity of internal organ
• basement membrane =lower surface of epithelium, secreted by cells
• no blood supply, depend on diffusion from capillaries for food and oxygen
• regenerate themselves easily
Classification of Epithelium
• by cell arrangement (simple, stratified) and cell shape (squamous, cuboidal, columnar)
• simple = one cell layer
• stratified = more than one cell layer
• squamous = flattened like fish scales
• cuboidal = cube-shaped like dice
• columnar = shaped like columns
Simple Epithelia
• simple squamous - single layer, filtration, rapid diffusion (alveoli, capillaries, serous
membranes)
• simple cuboidal - single layer on basement membrane (glands and ducts, kidney tubules and
surface of ovaries)
• simple columnar - single layer, tall close together (lines digestive tract from stomach to anus)
• pseudostratified (ciliated) columnar - appear at different heights above basement membrane,
absorption, secretion (lines respiratory tract)
Stratified Epithelia
• stratified squamous - several layers, receives frequent friction (esophagus, mouth, outer skin)
• stratified cuboidal/columnar - two cell layers, cuboidal at surface, fairly rare (ducts of large
glands) *not in table
• transitional - modified stratified squamous, change shape, subject to stretching (urinary
bladder, ureters)
Glandular Epithelia
• gland=one or more cells that secrete a product
• duct = channel leading from a gland to epithelial surface
• endocrine gland - ductless, secrete hormones directly into blood vessels (thyroid, adrenals,
pituitary)
• exocrine glands - have ducts, excrete product to internal or external surface (sweat, oil, liver,
pancreas)
Connective Tissue
• most abundant and widely distributed tissue
• most are well vascularized (good blood supply)
• tendons and ligaments have a poor blood supply
• cartilages are avascular
• made up of many cell types plus nonliving substances called the extracellular matrix
Extracellular matrix
Made of two elements in varying amounts:
• ground substance - water, adhesion proteins, large polysaccharide molecules
• fibers - collagen, elastic, reticular
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Name_______________________________
Types of Connective Tissue
• bone (osseous tissue) - rocklike hardness, calcium salt matrix, protection, support (skull,
bones)
• hyaline cartilage - collagen fibers, rubbery matrix (larynx, attaches ribs to sternum, ends of
bones, fetus skeleton)
• fibrocartilage - chondrocytes and collagen fibers, highly compressible (between vertebrae)
• elastic cartilage - elasticity (supports external ear)
• dense connective (dense fibrous) -collagen fibers, fibroblasts, ropelike (tendons-muscle to
bone, ligaments-bone to bone, lower layer of skin/dermis)
• areolar - soft, pliable, “cobweb”, cushions and protects, soaks up fluid during inflammation,
swelling/puffiness known as edema (widely distributed, holds organs together, underlies
mucous membranes lamina propria)
• adipose (fat) - areolar tissues in which fat cells predominate (subcutaneous tissue, protects
kidneys, eyeballs, hips, breasts)
• reticular - interwoven reticular fibers, support free blood cells (lymph nodes, spleen, bone
marrow)
• blood - blood cells and plasma, transports nutrients, gases, and wastes (in blood vessels)
Muscle Tissue
• Three types:
• skeletal - striated (stripes), multinucleated, voluntary movements (attached to skeletal bones)
• smooth - no striations, uninucleate, spindle-shaped, involuntary (walls of stomach, bladder,
uterus, and blood vessels)
• cardiac - striated, uninucleate, branching cells, intercalated disks (gap junctions that conduct
electrical impulse, involuntary (heart)
Nervous Tissue
• neurons and supporting cells - cytoplasm drawn out into long extensions, electrochemical
impulses (brain, spinal cord, nerves)
Tissue Repair (Wound Healing)
• Two major ways:
• ________________= replacement of destroyed tissue by same kind of cell
• _____________ = repair by dense (fibrous) connective tissue, the formation of scar tissue;
strong but lacks flexibility
• Which type used depends on type of tissue and severity. Clean cuts generally heal much
more successfully than ragged tears of tissue.
• Epithelia and connective tissues regenerate well. Mature cardiac muscle and nervous tissue
are ______________ and are repaired by fibrosis.
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