a&p i exam 2 review slides summer 2013 lectures 7-11 ch. 3 and ch. 4
TRANSCRIPT
A&P I Exam 2 Review SlidesSummer 2013
Lectures 7-11Ch. 3 and Ch. 4
2
Some Definitions…
Gene – segment of DNA that codes for a protein or RNA- About 30,000 protein-encoding genes in humans- DNA’s instructions are ultimately responsible for the ability of the cell to make ALL its components
*Chromatin – combination of DNA plus histone proteins used to pack DNA in the cell nucleus
Genome – complete set of genes of an organism- Human Genome Project was complete in 2001- Genomes of other organisms are important also
Genetic Code – method used to translate a sequence of nucleotides of DNA into a sequence of amino acids
3
Structure of Nucleic Acids
Figure from: Alberts et al., Essential Cell Biology, Garland Press, 1998
Purines: Adenine and Guanine (double ring)
Pyrimidines: Cytosine, Thymine, and Uracil (single ring)
4
Structure of DNA
A double-stranded DNA molecule is created by BASE-PAIRING of the nitrogenous bases via HYDROGEN bonds.
Notice the orientation of the sugars on each stand.
*DNA is an antiparallel, double-stranded polynucleotide helix
5'3'
5' 3'
5
Structure of DNA
Base pairing in DNA is VERY specific. - Adenine only pairs with Thymine (A-T) - Guanine only pairs with Cytosine (G-C)
Note that there are:
- THREE hydrogen bonds in G-C pairs
- TWO hydrogen bonds in A-T pairs
- A purine (two rings)base hydrogen bonds with a pyrimidine base (one ring)
Figure from: Martini, “Human Anatomy & Physiology”, Prentice Hall, 2001
Complementary base pairing…
6
DNA Replication
Figure from: Martini, “Human Anatomy & Physiology”, Prentice Hall, 2001
THINGS TO NOTE:
1. DNA is replicated in the S phase of the cell cycle
2. New strands are synthesized in a 5’ to 3’ direction
3. DNA polymerase has a proofreading function (1 mistake in 109 nucleotides copied!)
4. Semi-conservative replication describes pairing of post-replication strands of DNA (1 new, 1 old)
5’
5’
5’
5’
3’
3’
5’
3’
3’
3’
7
RNA
• RNA is a polynucleotide with important differences from DNA– Uses Uracil (U) rather than Thymine (T)– Uses the pentose sugar, ribose– Usually single-stranded
• There are three important types of RNA– mRNA (carries code for proteins)– tRNA (the adapter for translation)– rRNA (forms ribosomes, for protein synthesis)
8
Transciption/Translation
• Transcription – generates mRNA from DNA– Occurs in nucleus of the cell– Uses ribonucleotides to synthesize mRNA
• Translation – generates polypeptides (proteins) from mRNA– Occurs in the cytoplasm of the cell – Uses 3 components: mRNA, tRNA w/aa, and ribosomes
9
The Genetic Code
1. Codon – group of three ribonucleotides found in mRNA that specifies an aa
2. Anticodon – group of three ribonucleotides found in tRNA that allows specific hydrogen bonding with mRNA
3. AUG is a start codon and also codes for MET. UAA, UAG, and UGA are stop codons that terminate the translation of the mRNA strand.
Find the AMINO ACID SEQUENCE that corresponds to the following gene region on the DNA:
Template -> C T A A G T A C T
Coding -> G A T T C A T G A
11
tRNAs
Transfer RNAs (tRNA) function as ‘adapters’ to allow instructions in the form of nucleic acid to be converted to amino acids.
Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001
12
Eukaryotic Genes
Figure from: Alberts et al., Essential Cell Biology, Garland Publishing, 1998
The template strand of DNA is the one that’s transcribed.
The coding strand of DNA is used as the complementary strand for the template strand in DNA and looks like the codons.
13
Eukaryotic mRNA Modification
Figure from: Alberts et al., Essential Cell Biology, Garland Publishing, 1998
Newly made eukaryotic mRNA molecules (primary transcripts) undergo modification in the nucleus prior to being exported to the cytoplasm.
1. Introns removed2. 5' guanine cap added3. Poly-A tail added
14
The Fate of Proteins in the Cell
• Breakdown of proteins regulates the amount of a given protein that exists at any time.
• Each protein has unique lifetime, but the lifetimes of different proteins varies tremendously.
• Proteins with short life-spans, that are misfolded, or that become oxidized must be destroyed and recycled by the cell.
Enzymes that degrade proteins are called proteases. They are hydrolytic enzymes.
Most large cytosolic proteins in eukaryotes are degraded by enzyme complexes called proteasomes.
15
Types/Functions of Epithelial Tissue
• Functions of Epithelial Tissue– Physical protection– Control of permeability
• Secretion, Absorption, Filtration
– Provide sensation– Provide specialized secretions (glands)
• Types of epithelium1. Covering and Lining Epithelium
– External Surfaces, e.g., skin, Internal surfaces
2. Glandular Epithelium
16
Characteristics of Epithelial Tissue
• Specialized contacts with other cells
• Polarity (different ends of cell do different things)
• Avascularity (no blood supply)
• Regeneration (can divide to make new cells)
• Cellularity (lots of cells in close contact)
Remember: Epithelial tissues always have a free surface and a basement membrane
17
Basal Lamina
Two components:
Lamina Lucida - glycoproteins and fine protein filaments - Barrier for passage of substances from underlying tissue into epithelium
Lamina Densa - bundles of coarse protein fibers - gives basal lamina its strength
Formerly called: Basement membrane
Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004
Lamina = thin layer
18
Classification of Epithelial Tissues
• Shape– Squamous (Thin, flat, irregular in shape)– Cuboidal (Square or cuboidal)– Columnar (Rectangular, tall)
• Type of layering (stratification)– Simple (one layer)– Stratified (two or more layers)– Note that classification of stratified
epithelium is based on the shape of the superficial, not deep, layers
Epithelial tissues are classified according to both their:
19
Characteristics of Epithelial TissueSpecialized Contacts
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Tight junction – forces substances to go through cells, rather than being able to pass between them
Gap junction – allow rapid passage of small molecules/ions between cells
Desmosome – binds cells together firmly so they stay connected
20
Review
NAME OF ET DESCRIPTION STRUCTURE
LOCATION FUNCTION
SIMPLESQUAMOUS
a single layer of flattened cells
linings of air sacs, capillaries, lymph vessels, body cavities; covering ventral organs
diffusion, reduction of friction
SIMPLE CUBOIDAL
a single layer of cube-shaped cells with large centrally located nuclei
linings of kidney tubules, ducts of glands
absorption,secretion
SIMPLE COLUMNAR
a single layer of tall cells with basally located nuclei, goblet cells, & mucrovilli
lining of intestine protection,absorption,secretion
PSEUDO-STRATIFIEDCOLUMNAR
a single layer of tall cells with scattered nuclei, cilia, & goblet cells
lining of trachea,lining of fallopian tube
protection, secretion
21
Review
NAME OF ET DESCRIPTION STRUCTURE
LOCATION FUNCTION
STRATIFIEDSQUAMOUS
many layers of flattened cells
keratinized = epidermis;non-keratinized = lining of vagina, anus, throat, mouth
protection
TRANSITIONAL several layers of cells that change shape under pressure
lining of urinary bladder and ureters
Distensibility (able to stretch)
GLANDULAR simple cuboidal lining the ducts of glands
secretion
22
Review of Epithelial Tissues
• Exocrine glands have several different mechanisms of secretion– Merocrine
• Release of product from vesicles by exocytosis – none of cell is lost
– Holocrine• Entire cell is lost: packed with secretion and then bursts
• Ex: Unicellular = mucous gland; multicelluar = sweat gland, sebaceous gland, mammary gland, etc.
• Glands are specialized epithelium
– Secrete on to a surface (exocrine)
– Secrete into a duct (exocrine)
– Secrete into the blood (endocrine)
23
Membranes
Serous• line body cavities that lack openings to outside• reduce friction• inner lining of thorax and abdomen• cover organs of thorax and abdomen• secrete serous fluid
Mucous• line tubes and organs that open to outside world• lining of mouth, nose, throat, digestive tract, etc.• secrete mucus
Cutaneous• covers body• skin
A membrane is a combination of epithelium and connective tissue that covers and protects other structures and tissues. Technically, then, a membrane is an organ.
Synovial• surround joint cavities
24
Review of Connective TissuesNAME OF CT DESCRIPTION LOCATION FUNCTION
MESENCHYME Embryo gives rise to all other CT’s
AREOLAR gel-like matrix with fibroblasts, collagen and elastic fibers
beneath ET (serous membranes around organs & lining cavities)
diffusion, cushioning organs
ADIPOSE closely packed adipocytes with nuclei pushed to one side by fats
beneath skin, breasts, around kidneys & eyeballs
insulation, energy store, protection
RETICULAR network of reticular fibers in loose matrix
basement membranes,lymphatic organs
support
DENSEREGULAR
dense matrix of collagen fibers
tendons, ligaments attachment (high tensile strength)
DENSEIRREGULAR
loose matrix of collagen fibers
dermis of skin strength in several directions
25
Review of Connective TissuesNAME OF CT DESCRIPTION LOCATION FUNCTION
ELASTIC CT matrix of elastic fibers
lung tissue, wall of aorta
durability with stretch
HYALINECARTILAGE
chondrocytes in lacunae in amorphous matrix
embryonic. skeleton, costal cart, tip of nose, trachea, larynx
support
FIBRO-CARTILAGE
less firm than above intervertebral discs, pubic symphysis
tensile strength, shock absorber
ELASTICCARTILAGE
above plus elastic fibers
external ear, epiglottis
shape maintenance plus flexibility
BONE concentric circles of calcified matrix
Bones support, protection, movement, Ca ++ storage, hematopoiesis
BLOOD red cells, white cells and platelets in liquid plasma
in heart and blood vessels
transport of nutrients, wastes & gases
26
Name of CT
Different types of this CT
Main types of cells present
Main types of fibers present
Consistency of matrix Examples of Locations
CT Proper1) Areolar (Loose)2) Dense regular3) Dense irregular4) Adipose5) Reticular6) Elastic
1) Fibroblasts2) Fibroblasts3) Fibroblasts4) Adipocytes5) Fibroblasts6) Fibroblasts
1) Collagen, Elastic2) Collagen3) Collagen4) Reticular5) Reticular6) Elastic
Semi-liquid1) Skin, between muscles2) Tendons, ligaments3) Dermis 4) Body fat areas5) Stroma of liver, spleen6) Lungs, airways, arteries/heart
Cartilage 1) Hyaline2) Fibrocartilage3) Elastic
(All) Chondrocytes1) Collagen (sparse)2) Collagen (dense)3) Elastic
All types: Semi-solid, gelatinous;
rubbery
1) Ribs, ends of bones2) Intervertebral disks3) Pinna of ear, epiglottis
Bone 1) Dense2) Spongy
(All) Osteocytes Collagen Solid (hydroxyapatite)
1) Outer portions of bone2) Inner portions of bone
Blood--
1) RBCs2) WBCs3) Platelets (cell fragments)
Fibrinogen (soluble) Liquid Blood vessels, heart
Lymph -- Lymphocytes Reticular (in stroma of lymphoid organs)
Liquid Lymph vessels
Connective Tissue (CT) Summary Table
Three main components of ALL types of CT: cell, fibers, ground substance
-cyte = fully differentiated; -blast = young, actively synthesizing cell
27
Connective Tissue - Major Cell Types
Fibroblasts• fixed cell• most common cell; always in CT proper • large, star-shaped• produce fibers• produce ground substance
Macrophages• wandering cell• phagocytic• important in defense• derived from circulating monocytes
Mast cells are mediators of inflammation – see later…
28
Connective Tissue FibersCollagenous fibers
• thick• composed of collagen• great tensile strength • hold structures together• abundant in dense CT• tendons, ligaments
Elastic fibers• bundles of microfibrils embedded in elastin• fibers branch• elasticity• vocal cords, air passages
Reticular fibers• very thin collagenous fibers• highly branched• form supportive networks
29
The “Ground Substance” of CT
Figures from: Alberts et al., Essential Cell Biology, Garland Press, 1998
VERY hydrophilic!
**Function: Very active in controlling passage of substances through this portion of the matrix and keeping CT hydrated
GAGs = glycosaminoglycans (negatively charged polysaccharides); a major molecule in ground substance
glucosamine
30
Tendons and Ligaments
Tendons: Connect muscle to boneLigaments: Connect bone to boneAponeuroses: Broad, fibrous sheets; usually attach muscle to muscle (or bone)
31
CT Framework of the Body
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Fascia: layers of fibrous connective tissue covering and separating muscle. It connects the organs of the dorsal and ventral cavities with the rest of the body
Provide: - Strength - Stability - Organ position - Conduits
32
Muscle – Overview
• General characteristics– Elongated cells with special properties– Muscle cells (myocytes) = muscle fibers– Contractile (major property of all muscle)– Use actin (thin) and myosin (thick) for contraction
• Three types of muscle tissue– Cardiac (involuntary)– Skeletal– Smooth
33
Review of Muscle TypesNAME OFMUSCLETISSUE
DESCRIPTION OFSTRUCTURE
TYPE OFCONTROL
LOCATION FUNCTION
SKELETALMUSCLE
long, thin fibers with many nuclei and striations
Voluntary attached to bones to move bones
SMOOTHMUSCLE
spindle shaped cells with one centrally located nucleus, lacking striations
Involuntary walls of visceral hollow organs, irises of eyes, walls of blood vessels
to move substances through passageways (i.e. food, urine, semen),
constrict blood vessels, etc
CARDIAC MUSCLE
a network of striated cells with one centrally located nucleus attached by intercalated discs
- Intercalated disks consist of : 1)gap junctions and 2) desmosomes
Involuntary heart pump blood to lungs and body
34
Nervous Tissue• found in brain, spinal cord, and peripheral nerves• conduction of nerve impulses• basic cells are neurons• sensory reception• neuroglial cells are supporting cells
35
Introduction to Inflammation
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Restoration of tissue homeostasis after injury or infections involves two processes, in order: 1) inflammation and 2) repair
Main signs of inflammation: Redness, heat, pain, swelling, and loss of function
(Inflammation = ‘-itis’)
Histamine
HistamineHeparin