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163 Cards in this Set
- Front
- Back
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DNA
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Double Standed Helix (anti-parallel)
Bases are G,C,A,T Sugar is Deoxyribose Replicates from self(semiconservative) From 5' to 3' |
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RNA
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Single stranded
Bases G,C,A,U Sugar is Ribose Transcribed from DNA template(anti-sense strand) |
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Bases in DNA
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Purines Pyrimidines
G-------------C A-------------T |
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Bases in RNA
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Purines Pyrimidines
G--------------C A--------------U |
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Cell Cycle
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G1 - 1st Growth phase
S - Synthesis of DNA (chromosome replication) G2- 2nd Growth phase M - Mitosis C - Cytokinesis |
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Meiosis
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Prophase I-
Metaphase I- Anaphase I- Telophase I- Prophase II- Metaphase II- Anaphase II- Telophase II- |
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Prophase I
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Chromosomes condense: homologous chromosomes come together to form tetrads - crossing over occurs (2n)
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Metaphase I
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Chromosomes line up on metaphase plate (2n)
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Anaphase I
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Separation of homologous chromosomes (2n)
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Telophase I
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Two daughter cells form. Cytokinesis. (n)
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Prophase II
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New Mitotic spindle forms (n)
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Metaphase II
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Chromosomes line up on metaphase plate. (n)
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Anaphase II
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Separation of chromatids (n)
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Telophase II
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Four daughter cells result from original parent cell. Cytokinesis. (n)
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Differences between mitosis and meiosis
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Mitosis - production of cells for growth and repair: One division: two diploid (2n)daughter cells produced: In prophase I, homologous chromosomes do not synapse
Meiosis- Production of gametes, induces genetic variation in gametes: Two divisions with no DNA replication between divisions: Production of four haploid (n) daughter cells.In prophase I, homologous chromosomes synapse, forming tetrads. Subsequently, crossing-over occurs. |
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Viruses
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Viruses are obligate intracellular parasites that can only reproduce in host cell.
Features: ~Host and tissue specificity ~Contain DNA OR RNA(not both) ~RNA viruses must contain specific enzymes for replication of RNA |
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Bacteriophage
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DNA is injected into host, usually leaving capsid and tail outside of cell.
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Mitosis
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Prophase- Chromosomes condense
Metaphase- Chromosomes line up on metaphase plate Anaphase- Separation of chromatids Telophase- Daughter nuclei form |
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Life Cycle of a DNA Bacteriophage Virus
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1. Virus attaches to cell wall
2. Virus injects its DNA into cell 3. The DNA is replicated and transcribed into mRNA repeatedly using enzymes and substrates of the cell 4. mRNA is translated into proteins 5. Self-assembly of new viruses using the new DNA and protein 6. New viruses begin digesting cell wall 7. Cell swells and bursts, releasing the viruses 8. Viruses attach to other cells |
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Retroviruses
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Retroviruses are a class of virus that reproduce by transcribing their RNA into DNA. Isolated retroviruses contain the enzyme reverse transcriptase for this purpose since host cells lack this enzyme. Retroviruses include many cancer-causing viruses as well as the virus that causes AIDS, the human immunodeficiency virus (HIV).
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Retrovirus:life cycle of the HIV virus
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1. a Virus attaches to cell membrane
2. Viral envelope merges with cell membrane 3. Single-stranded RNA released into cell 4. Single-stranded DNA transcribed from this using reverse transcriptase 5. Complementary DNA strand synthesized using the single-stranded DNA as a template 6. The double-stranded DNA is incorporated into the cell's genome (this DNA is called a provirus) 7. Viral genes are transcribed into mRNA, which are then translated into viral proteins or are packaged as genetic material in new viruses 8. New viruses, complete with RNA, reverse transcriptase, capsids, and envelopes, exit the cell and find other cells to infect |
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The Five Kingdoms
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Monera
Protista Fungi Plants Animals |
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Gene Transfer in Bacteria
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Bacteria reproduce by binary fission, an asexual process. Since they do not reproduce sexually, they have evolved other means of creating genetic variation in their offspring.
Conjugation - The transfer of genetic material from one cell to another via a temporary mating bridge. The "male" transfers DNA to the "female" and not vice versa. Transduction - The transfer of genetic material from one cell to another via a virus. Transformation - The assimilation of external genetic material by a cell. |
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Fungi
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eukaryotic, primarily multicellular, lack flagella, and most have cell walls made of chitin (a structural polysaccharide). All are heterotrophs, acquiring nutrients by absorption. They digest their food by secreting hydrolytic enzymes.
Fungi consist mostly of hyphae, which branch and form a net-like structure called a mycelium. Most fungi have their hyphae partitioned into cells, although some are coenocytic (i.e. aseptate). Fungi reproduce by dispersing great numbers of spores, which germinate into hyphae. Early reproduction is usually asexual, with the haploid state persisting throughout. Later reproduction is sexual: cell fusion occurs forming a diploid cell, which undergoes meiosis to form haploid spores. Thus, genetic variation is introduced. |
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Viruses
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0.02 - 0.04 microns (transmission electron microscopy required)
Lack metabolic & reproductive machinery No ER or ribosomes No histones |
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Prokaryotes
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Less than 1 micron to 3 microns
Plasma membrane but no nuclear membrane, etc. No ER. Ribosomes are "free." Transcription & translation are simultaneous No histones |
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Eukaryotes
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5 to 100 microns
Plasma membrane, nuclear membrane, membranes of various organelles Have ER. Some ribosomes "free"; others attached to ER. Transcription & translation NOT simultaneous Have Histones (proteins found in chromosomes) |
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Parts of the Nephron
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Bowman's capsule
Proximal tubule Descending loop Ascending loop Distal tubule Collecting duct |
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Bowman's capsule
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Filtration of blood
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Proximal tubule
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Reabsorption (active transport) of glucose, amino acids, Ca2+, other electrolytes. Secretion of H+, K+, NH3, creatine, organic acids.
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Descending loop
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Diffusion of water and electrolytes
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Ascending loop
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Active reabsorption of Cl- (Na+ follows passively). Counter-current sytem establishes high osmotic pressure in medulla.
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Distal tubule
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Active reabsorption of Na+ (Cl- follows passively). Secretion of H+, K+, NH3.
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Collecting duct
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reabsoption of water by osmosis (ADH-dependent). Secretion of H+, K+, NH3.
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Genetics
(Basic Principles) |
Inherited characteristics (traits) are passed from generation to generation by means of genes.
Genes are comprised of DNA and are contained in chromosomes. A locus is a particular place along the length of a certain chromosome where a given gene is located. Alternative versions of genes that occupy a certain locus are called alleles. |
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Mendelian Inheritance
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For a given trait, an organism inherits two genes (or alleles), one from each parent. The genes are located at the same locus on a homologous pair of chromosomes. The two alleles may be the same, in which case the organism is said to be homozygous for that trait, or different, in which case the organism is said to be heterozygous for that trait. If the organism is heterozygous, then usually one of the alleles is dominant and is fully expressed in the phenotype, and the other allele is recessive and is not expressed.
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Law of Segregation
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During gametogenesis, the two alleles for each trait separate and go into different gametes so that each gamete contains only one allele.
If the parent is homozygous, each gamete will carry the same allele. If the parent is heterozygous, 50% of the gametes will carry one allele and 50% will carry the other allele. The law of segregation is concerned with one trait, one locus. Mendel also derived a rule for the inheritance patterns observed when there are two traits of interest. |
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Law of Independent Assortment
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Each pair of alleles segregates independently of other pairs of alleles provided the different pairs of alleles are on different pairs of homologous chromosomes.
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Monohybrid Cross
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A monohybrid cross is a breeding experiment that is concerned with differences in only one trait.
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Dihybrid Cross
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A dihybrid cross is a breeding experiment that is concerned with differences in two traits.
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Sex Determination
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In humans and many other animals, sex is determined by the sex chromosomes, X and Y. Males have an X and a Y chromosome, while females have two X chromosomes. The probability of having a son or daughter is always about 50%.
Note that in males, the X chromosome always comes from the mother, while the Y chromosome always comes from the father. |
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Sex-linked Inheritance
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Genes that are on the sex chromosomes are said to be sex-linked. Genetic disorders that are sex-linked are often characterized by mothers being carriers and their sons being affected with the disorder.
The X chromosome is much larger than the Y chromosome and so carries more genetic information. For instance the genes for hemophilia and color blindness, both of which are recessive, are located on the X chromosome. The Y chromosome does not have loci for these genes or their alleles; therefore, when a male inherits an X chromosome from his mother containing the hemophilia gene, the gene is expressed resulting in the male being hemophilic. |
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Mutations
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A mutation is a change in the sequence of nucleotides in a gene. Mutations can occur spontaneously as a result of errors during DNA replication, repair, or recombination. Ionizing radiation and certain chemicals can also cause mutations.
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Base-pair substitutions
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Replacement of a base-pair by another base-pair. Yet there may be no effect on the protein coded for since the genetic code is redundant. If a different amino acid is incorporated into the protein, the effect may still be negligible if the new amino acid has similar properties to the one it has replaced, or if the location of it is far from the active site, etc. of the protein. However, some substitutions are significant, e.g. sickle-cell anemia is due to a single base-pair substitution mutation that occurred many generations ago.
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Base-pair insertions and deletions
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Additions or losses of one or more base-pairs. These are usually more deleterious than substitutions. This is because mRNA is read as triplets of bases. If three nucleotide pairs are inserted or deleted, the problem may not be very significant. However, if one or two base-pairs are inserted or deleted, a frame-shift occurs causing all bases downstream to be read incorrectly. A non-functional protein is likely unless the frame-shift mutation occurs near the end of the gene.
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Species
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A population or group of populations that have the potential to interbreed in nature.
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Population
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A localized group of individuals belonging to the same species.
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Natural Selection
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Natural selection is the process whereby the organisms best adapted to their environment survive and reproduce at higher rates than those less well adapted.
Natural selection is possible because of: variation among individuals in a population and the tendency for a population to produce more offspring than the environment can support. Individuals that are well adapted (fit) survive and reproduce and leave relatively more offspring than individuals that are not well adapted (differential reproduction). In this way, the proportion of "desirable" genes in the gene pool of a population increases. |
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Comparative Anatomy
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Evidence of the descent of separate species from a common ancestor can be found by comparing anatomical structures (as well as by other means such as examining DNA and the fossil record). Homologous structures are ones that are anatomically similar but may not serve similar functions. For instance, the forelimbs of all mammals are homologous structures since they are constructed from the same skeletal elements even though they may serve vastly different functions in different species.
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Chordate Features
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Humans are members of the chordate phylum, as are all vertebrates and some invertebrates. Chordates are characterized by possessing the following four features at some point in their development:
Notochord- Longitudinal, flexible rod between gut and nerve cord. Dorsal, hollow nerve cord-forms the central nervous system. It is derived from a plate of ectoderm that rolls into a tube. Pharyngeal slits- these are like gills in fish, although gas exchange may or may not occur. Postanal tail- A tail extending beyond the anus. |
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Vertebrate Features
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Vertebrates are a subphylum of chordates. They include fish, amphibians, reptiles, birds, and mammals. In addition to possessing the above four chordate features at some point in their development, most vertebrates also have the following features:
Highly cephalized Endoskeleton Vertebrae Skull Axial skeleton Appendicular skeleton Closed circulatory system Kidneys |
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Pathways by which Substances Cross Membranes
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Through lipid bilayer - lipophillics, O2, CO2, fatty acids
Through protein channel - hydrophillics, charged ions, Na+, K+, Ca2+ : use of integral membrane protein Via Facilitated diffusion - Glucose : use of integral membrane protein Via Active transport (energy required)- Against Concentration Gradient - H+, amino acids, glucose, Na+, K+, Ca2+ : use of integral membrane protein |
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Scientific units of measure
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1cm = 10mm
1mm = 1000um 1um = 1000nm 1nm = 10A(angstrom units) 1um = 10,000A |
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Gram-positive bacteria
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Cell wall consisting of thick layer of peptidoglycans(sugars/amino acids)
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Gram-negative bacteria
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Surrounded by a complex wall structure: thin inner layer of peptidoglycans surrounded by an "outer membrane" of lipopolysaccharide and protein which serves to control the entrance of water soluables into the bacterial cell
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Prokaryotic cellular extentions/adaptations
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Flagellum - protein rod (lacking microtubules) attached to cell by hook and swivel
Pili - hollow protein tubes that attach to bacteria surfaces and transfer DNA during conjugation Slime layer/capsule- loose polysaccharide gel outside the cell wall complex. Protects parasitic bacteria againts host defense mechanisms. |
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Functional Eukaryotic Chromosome Components
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1. A centromere sequence is necessary to integrate the chromosome into the spindle during mitosis/meiosis. (each chromosome has 1 centromere)
2. At least one replication initiation sequence is needed to initiate DNA replication in the chromosome. (most eukaryotic chromosomes contain multiple replication initiation sequences) 3.A telomere sequence is needed at each end of the chromosome to allow replication with out loss of critical sequences |
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Chromatin Structure
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Each unreplicated eukaryotic chromosome contains a single linear DNA molecule complexed with protein to form chromatin. 2:1(protein:DNA)
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Histones
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Most numerous category of proteins in chromatin 1:1(histone:DNA)
Histones contain numerous AA's with side chains resulting in a net + surface charge which binds ionically to charged phosphate groups in DNA. Their chief functions are to compact and control the long threads of DNA. They compact the DNA by interacting with each other to form a structure like a compact spool. Two turns of DNA are wrapped around this spool, forming the subunits known as nucleosomes and decreasing the effective length of DNA eightfold. |
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Nucleosome
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repeating subunits of chromatin, consisting of a DNA chain coiled around a core of histones.(Aggregate of histones and DNA)
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Euchromatin
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Chromosomal material that is genetically active and stains lightly with basic dyes.
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Heterochromatin
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Tightly coiled chromosomal material that stains deeply during interphase and is believed to be genetically inactive.
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Cytosol
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The fluid component of cytoplasm, containing the insoluble, suspended cytoplasmic components. In prokaryotes, all chemical reactions take place in the cytosol. In eukaryotes, the cytosol surrounds the organelles.
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Free Ribosomes
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A minute round particle composed of RNA and protein that is found in the cytoplasm of living cells and serves as the site of assembly for polypeptides encoded by messenger RNA.
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Smooth ER
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tubular in form and is involved in the synthesis of phospholipids, the main lipids in cell membranes. Smooth endoplasmic reticulum is the site of the breakdown of toxins and carcinogens in the liver, the conversion of cholesterol into steroids in the gonads and adrenal glands, and the release of calcium ions in the muscles, causing muscle contraction. The smooth endoplasmic reticulum also transports the products of the rough endoplasmic reticulum to other cell parts, notably the Golgi apparatus.
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ER
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An organelle consisting of a network of membranes within the cytoplasm of eukaryotic cells that is important in protein synthesis and folding and is involved in the transport of cellular materials. The endoplasmic reticulum can be continuous in places with the membrane of the cell nucleus. The function of the endoplasmic reticulum can vary greatly with cell type, and even within the same cell it can have different functions depending on whether it is rough or smooth.
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Rough ER
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a series of connected flattened sacs that have many ribosomes on their outer surface. Rough endoplasmic reticulum synthesizes and secretes serum proteins (such as albumin) in the liver, and hormones (such as insulin) and other substances (such as milk) in the glands.
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Golgi Apparatus
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An organelle in eukaryotic cells that stores and modifies proteins for specific functions and prepares them for transport to other parts of the cell. The Golgi apparatus is usually near the cell nucleus and consists of a stack of flattened sacs. Proteins secreted by the endoplasmic reticulum are transported into and across the Golgi apparatus by vesicles and may be combined with sugars to form glycoproteins. The modified products are stored in vesicles (such a lysosomes) for later use or transported by vesicles to the plasma membrane, where they are excreted from the cell.
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Lysosome
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A cell organelle that is surrounded by a membrane, has an acidic interior, and contains hydrolytic enzymes that break down food molecules, especially proteins and other complex molecules. Lysosomes fuse with vacuoles to digest their contents. The digested material is then transported across the organelle's membrane for use in or transport out of the cell.
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Mitochondria
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A structure in the cytoplasm of all cells except bacteria in which food molecules (sugars, fatty acids, and amino acids) are broken down in the presence of oxygen and converted to energy in the form of ATP. Mitochondria have an inner and outer membrane. The inner membrane has many twists and folds (called cristae), which increase the surface area available to proteins and their associative reactions. The inner membrane encloses a liquid containing DNA, RNA, small ribosomes, and solutes. The DNA in mitochondria is genetically distinct from that in the cell nucleus, and mitochondria can manufacture some of their own proteins independent of the rest of the cell. Each cell can contain thousands of mitochondria, which move about producing ATP in response to the cell's need for chemical energy. It is thought that mitochondria originated as separate, single-celled organisms that became so symbiotic with their hosts as to be indispensible. Mitochondrial DNA is thus considered a remnant of a past existence as a separate organism.
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Cellular Respiration
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The process of cell catabolism in which cells turn food into usable energy in the form of ATP. In this process glucose is broken down in the presence of molecular oxygen into six molecules of carbon dioxide, and much of the energy released is preserved by turning ADP and free phosphate into ATP. Cellular respiration occurs as a series of chemical reactions catalyzed by enzymes, the first of which is glycolysis, a series of anaerobic reactions in which glucose (a 6-carbon molecule) is split into two molecules of lactate (a 3-carbon molecule), producing a net gain of two ATP molecules. In a series of aerobic reactions, lactate is converted to pyruvate, which enters the mitochondrion and combines with oxygen to form an acetyl group, releasing carbon dioxide. The acetyl group (CH3CO) is then combined with coenzyme A as acetyl coenzyme A, and enters the Krebs cycle. During this series of reactions, each acetyl group is oxidized to form two molecules of carbon dioxide, and the energy released is transferred to four electron carrier molecules. The electron carrier molecules then release their energy in a process that results in the pumping of protons (hydrogen ions) out across the inner membrane of the mitochondrion. The potential energy of the protons generated by one acetyl group is later released when they recross the membrane and are used to form three molecules of ATP from ADP and phosphate in the process of oxidative phosphorylation. The pyruvate from one molecule of glucose drives two turns of the Krebs cycle. Thus, during cellular respiration one molecule of glucose, as well as oxygen, ADP, and free phosphate are catabolized to yield six molecules of carbon dioxide and an increase in usable energy in the form of eight molecules of ATP.
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Cytoskeleton
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The internal framework of a cell, composed of a network of protein filaments and extending throughout the fluid of the cell (the cytosol). The cytoskeleton consists mainly of actin filaments, intermediate filaments and microtubules and plays an important role in cell movement, shape, growth, division, and differentiation, as well as in the movement of organelles within the cell. All eukaryotic cells have a cytoskeleton.
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Microfilaments (Actin)
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minute fibers located throughout the cytoplasm of cells, composed of actin and functioning primarily in maintaining the structural integrity of a cell.
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Intermediate Filaments
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The domain structure of Intermediate Filaments molecules is conserved. Each protein has a non-alpha-helical (globular) domain at the N and C-termini which surrounds the alpha-helical rod domain. The basic building block for IFs is a parallel and in register dimer. The dimer is formed through the interaction of the rod domain to form a coiled coil. Cytoplasmic IF assemble into non-polar unit-length filaments which then assemble into longer structures.
The anti-parallel orientation of tetramers means that, unlike microtubules and microfilaments which have a plus end and a minus end, IFs lack polarity. Cytoplasmic IF do not undergo treadmilling like microtubules and actin fibers, but they are dynamic. |
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Microtubules
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Microtubules are polymers of α- and β-tubulin dimers. The tubulin dimers polymerize end to end in protofilaments. The protofilaments then bundle in hollow cylindrical filaments. Typically, the protofilaments arrange themselves in an imperfect helix with one turn of the helix containing 13 tubulin dimers each from a different protofilament. Another important feature of microtubule structure is polarity. Tubulin polymerizes end to end with the α subunit of one tubulin dimer contacting the β subunit of the next. Therefore, in a protofilament, one end will have the α subunit exposed while the other end will have the β subunit exposed. These ends are designated (−) and (+) respectively. The protofilaments bundle parallel to one another, so in a microtubule, there is one end, the (+) end, with only β subunits exposed while the other end, the (−) end, only has α subunits exposed.
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Centriole
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centriole /cen·tri·ole/ (sen´tre-ol) either of the two cylindrical organelles located in the centrosome and containing nine triplets of microtubules arrayed around their edges; centrioles migrate to opposite poles of the cell during cell division and serve to organize the spindles. They are capable of independent replication and of migrating to form basal bodies.
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Eukaryotic Flagellum
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A eukaryotic flagellum is a bundle of nine fused pairs of microtubule doublets surrounding two central single microtubules. The so-called "9+2" structure is characteristic of the core of the eukaryotic flagellum
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Cilia
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An organelle found in eukaryotic cells. Cilia are tail-like projections extending approximately 5–10 micrometers outwards from the cell body.
There are two types of cilia: motile cilia, which constantly beat in a single direction, and non-motile cilia, which typically serve as sensory organelles. |
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Cell-cell junctions
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Cell-cell junctions can be classified into three functional types
occluding junctions: function to seal cells together in an epithelial sheet adhesive junctions: mechanically attach cells to one another or to the ECM communicating junctions: allow direct passage of chemical or electrical signals from cell to cell |
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Stains
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Generally, stains are neutral salts having both acidic and basic radicals
Basic dyes - have basicradicals and structures stained by it are Basophillic Acidic dyes - contain acidic radicals and structures stained by it are acidophillic |
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Hematoxylin
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Common histological stain - stains nuclei blue
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Eosin and acidic dyes
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stain cytoplasm
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Iron hematoxylin
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stains chromosomes, mitochondria, Golgi complex and contractile elements black or dark blue
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Carmine
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stains nuclei purple
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Basic aniline dyes
toluidine blue, azure A and methylene blue) |
stain mucopolysaccharides metachromatically
(metachromatic - A stain that has the ability to produce different colors in various histological or cytological structures.) |
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Mallory's connective tissue stain
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stains collagen fibers bright blue, nuclei red/orange and other cell components blue red orange or purple
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Silver impregnation staining
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Method to stain reticular fibers brown
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Histochemical methods
(test to determine composition) |
Proteins - yellow w/picric acid
Carbohydrates - glycogen by PAS test(purple) Lipids - sudan dyes or osmic acid Nucleic acids- feulgen reaction (DNA) ribonuclease(RNA) Both DNA and RNA are basophillic because they are both acids |
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Fixation
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Modification of cell to resist further treatments and also to makefurther treatments possible.
Coagulant- methanol, ETOH. acetone, nitric acid, HCL, picric acid, trichloracetic acid and mercuric chloride Noncoagulant- formaldehyde, glutarahyde, osmium tetroxide, potassium dichromate, acetic acid and potassium permaganate Subcategories: Additive:osmium tetroxide, formaldehyde and glutaraldehyde Nonadditive: methanol, ETOH and acetone |
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Histological preparation
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1. Fixation - kills and preserves cells
2. Dehydration - H2O is removed via alcohol 3. Embedding - places tissue in solid medium (parafin/plastic) 4. Sectioning - cut in sections 5. Staining -dyes for light microscopy and heavy metals for electron microscopy |
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Nucleotides
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The monomers assembled to produce more complex nucleic acids. Made of three components:
1. Pentose sugar - five carbon sugar either (ribose or deoxyribose) 2. Nitrogenous base - purine (6-membered ring + 5-membered ring) or pyrimadine (6-membered ring) 3. Phosphate - each nucleotide contains a mono,di or triphosphate groups |
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Energy transfer via nucleotide
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If more than one phosphate group is attached to a nucleotide the bonds attaching the 2nd and 3rd groups are less stable and can be easily hydrolyzed for energy. ATP is the most widely used neucleotide triphosphate.
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Nucleotide base pairing
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Pair with complimentary nucleotides by forming hydrogen bonds between their nitrogenous bases:
A -> U or T via 2 H bonds G -> C via 3 H bonds |
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Nucleotide functions in cells
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1. Nucleotide triphosphates transport energy
2. Nucleotide triphosphates serve as monomers for the synthesis of RNA and DNA 3. Nucleotides may be modified into chemical signals for use within a cell(cyclic AMP) |
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RNA Functions
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mRNA - codes for the AA sequence of polypeptide chains
tRNA- carries AA's into protein synthesis rRNA - forms the structural framework of the ribosomal subunits snRNA - contain small RNA molecules remove introns from mRNA in eukaryotes |
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Genetic information flow in cells
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1. DNA replication
2. Transcription (RNA synthesis) 3. Translation (protein synthesis) Proteins directly or indirectly interact with the environment of the cell to produce the phenotype of the cell. |
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Protein structure
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Composed of 20 different AA's that share common backbone:
Amino group + carbon atom (alpha carbon) + carboxyl group The ultimate structure differs because of side chain structure attached to alpha carbon |
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Amino acid sequence (primary structure)
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Interacts with the polypeptide's environment and with other functional components in the cell.
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Conducting passages of the respiratory system
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1. external nares
2. nasal cavity with conchae, meatuses, and sinuses 3. internal (posterior) nares 4. nasopharnyx 5. oropharnyx 6. laryngeal pharnyx 7. larynx (w/false and true vocal cords) 8. trachea 9.primary(left and right) bronchi 10. secondary bronchi 11. tertiary bronchi 12. respiratory bronchioles 13. alveolar ducts 14. alveolar sacs 15. alvioli |
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Upper respiratory tract Function
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1. Removal of inhaled particles; filtration via hairs and mucous.
2. Humidification and heating of inhaled air mucous is moved by action of the ciliary elevator(system of ciliated cells. Mucous is either expactorated or swallowed |
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Lower respiratory tract function
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No ciliated cells present.
Removal of foreign particles accomplished via macrophage and leukocytes with drainage into lymphatics. Gas exchange occurs. |
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Respiration Process
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1. ventilation of the lungs
2. gas exchange between lungs and blood 3. transport of gases in the blood 4. gas exchange between blood and interstitial fluids of the body |
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Respiratory minute ventilation
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tidal volume x repiration rate
average Respiratory minute ventilation is 6 Liters per minute 500ml x 12(breaths per minute)=6 liters per minute |
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Inspiration
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Thorasic cavity expands
Volume ↑ Air rushes in to respiratory tract due to creation of negative pressure Musculature: diaphram (phrenic nerve) contraction causes descention of as much as 7cm External intercostals (intercostal nerves) contraction raises rib cage |
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Expiration
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Relaxation of diaphram and external intercostals
Stabilaztion of rib cage by internal intercostals and contraction of abdominal muscles, plus elasticity of lung, returns the organ to normal pre-repiratory resting phase. Generally speaking normal respiration does not involve much utilization of abdominal muscles untill ventilation exceeds 40L/minute. By contracting the abdominal muscles the contents of the abdomen are pushed upwards exerting force on the diaphram helping to force exhalation. |
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Positive pressure breathing
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Positive pressure breathing occurs during resucitation. Pressure at the nose and mounth (atmospheric pressure) is made greater than the alveolar gas pressure thus creating a pressure gradient
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Negative pressure breathing
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Involves the lowering of the alveolar presure below that of atmospheric pressure. (use of iron lung or normal breathing process)
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Importance of suffactant in maintaining alveolar stability
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When the lung returns to resting state the surface area and volume decreases thus ↑ pressure and forcing gas to rush out. The loss of gas creates an area of lower pressure in the alveolar sacs. The surractant present becomes compressed and increases the surface tension. It is this increase in surface tension that keeps the alveolar sacs from collapsing despite the lowered gas pressure.
Inability to produce surfactant will result in repiratory failure because lungs will collapse with each breath. |
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Neuronal control of breathing
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Autonomal control:
medulla - ventral(deep inspiration) Dorsal(expiration) rythmicity- 12-15 per/min is under control of pons and medulla via input of afferent vagal stretch receptors in lung Parasympathetic stimulation: causes bronchoconstriction and increase in airway resistance Sympathetic stimulation: Bronchodialation |
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Ideal Gas law
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PV = nRT
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Charles Law
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V1/T1 = V2/T2
(proportional relationship) |
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Boyle's Law
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P1V1 = P2V2
(proportional relationship) |
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Avogadro's Law
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n1/V1 = n2/V2
(proportional relationship) |
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pH
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pH = -log[H+]
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Dilution
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MiVi = MfVf
(where i is initial and f is final) |
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Density
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p = m/v
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Pressure
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P = F/A
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Nervous system
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Central:
Brain and spinal cord Peripheral: Peripheral nerves and ganglia Further divided into somatic and visceral(autonomic) |
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Nervous tissue
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nerve cells, their processes and supportive elements (Neuroglia -CNS)(schwann cells-peripheral)
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Neuron
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a nerve cell; any of the conducting cells of the nervous system, consisting of a cell body, containing the nucleus and its surrounding cytoplasm, and the axon and dendrites.
Neurons are highly specialized cells having two characteristic properties: irritability, which means that they are capable of responding to stimulation; and conductivity, which means that they are able to conduct impulses. They are composed of a cell body (the neurosome or perikaryon), containing the nucleus and its surrounding cytoplasm, and one or more processes (nerve fibers) extending from the cell body. The processes are actually extensions of the cytoplasm surrounding the nucleus of the neuron. A nerve cell may have only one such slender fiber extending from its body, in which case it is classified as unipolar. A neuron having two processes is bipolar, and one with three or more processes is multipolar. Most neurons are multipolar, this type of neuron being widely distributed throughout the central nervous system and autonomic ganglia. The multipolar neurons have a long single process called an axon and several branched extensions called dendrites. The dendrites receive stimuli from other nerves or from a receptor organ, such as the skin or ear, and transmit them through the neuron to the axon. The axon conducts the impulses to the dendrite of another neuron or to an effector organ that is thereby stimulated into action. Many processes are covered with a layer of lipid material called myelin. Peripheral nerve fibers have a thin outer covering called the neurilemma. |
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afferent neuron
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one that conducts a nervous impulse from a receptor to a center
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efferent neuron
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one that conducts a nervous impulse from a center to an organ of response.
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motoneuron
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a neuron having a motor function;an efferent neuron conveying motor impulses.
Three main types: lower motoneuron: a peripheral neuron whose cell body lies in the ventral gray columns of the spinal cord and whose termination is in a skeletal muscle. peripheral motoneuron: in a reflex arc, a motoneuron that receives impulses from interneurons. upper motoneuron: a neuron in the cerebral cortex that conducts impulses from the motor cortex to a motor nucleus of one of the cerebral nerves or to a ventral gray column of the spinal cord. |
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multisensory neuron
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a neuron in the cerebral cortex or subcortical regions that can receive input from more than one sensory modality.
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Dendrites
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1. Direct extension of cyctoplasm
2. Generally, multiples 3. Purpose is to increase surface area(dendritic zone) to allow for synaptic interaction |
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Axon
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the process of a nerve cell along which impulses travel away from the cell body. It branches at its termination, forming synapses at other nerve cells or effector organs. Many axons are covered by a myelin sheath formed from the cell membrane of a glial or Schwann cell.
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axon hillock
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the elevation on the perikaryon from which the axon emerges.
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axon telodendrion
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extensive terminal branches of the axon before terminating on the effector organ.
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axon terminals
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the axonal structure capable of forming a synapse with another axon.
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Nodes of Ranvier
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There are gaps between the myelin sheath cells known as the Nodes of Ranvier. At those uncovered areas of the axon membrane, the ion exchange necessary for the production of an action potential can take place. The action potential at one node is sufficient to excite a response at the next node, so the nerve signal can propagate faster by these discrete jumps than by the continuous propagation of depolarization/repolarization along the membrane. This enhanced signal transmission is called salutatory conduction.
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myelin sheath
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The insulating envelope of myelin that surrounds the core of a nerve fiber or axon and facilitates the transmission of nerve impulses. In the peripheral nervous system, the sheath is formed from the cell membrane of the Schwann cell and, in the central nervous system, from oligodendrocytes.
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Action potential
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1. A stimulus is received by the dendrites of a nerve cell. This causes the Na+ channels to open.
2.The Na+ influx drives the interior of the cell membrane up to about +30 mV. (Depolarization) 3.The Na+ channels close and the K+ channels open. Since the K+ channels are much slower to open, the depolarization has time to be completed. 4. W/K+ channels open membrance begins to repolarize back toward its rest potential. 5. repolarization typically overshoots the rest potential to about -90 mV. This is called hyperpolarization and would seem to be counterproductive, but it is actually important in the transmission of information. Hyperpolarization prevents the neuron from receiving another stimulus during this time, or at least raises the threshold for any new stimulus. 6.the Na+/K+ pumps eventually bring the membrane back to its resting state of -70 mV . |
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Synapse
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the site of functional apposition between neurons, where an impulse is transmitted from one to another, usually by a chemical neurotransmitter released by the axon terminal of the presynaptic neuron. The neurotransmitter diffuses across the gap to bind with receptors on the postsynaptic cell membrane and cause electrical changes in that neuron (depolarization/excitation or hyperpolarization/inhibition).
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Acetylcholine
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Where found:
Neuromuscular junctions, Autonomic nervous system and brain Actions: Excites muscles, decreases heart rate, and relays various signals in the autonomic nervous system and brain |
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Norepinephrine
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Location:
Sympathetic nervous system and brain Actions: Regulated the activity of Visceral organs and some brain functions |
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Dopamine
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Location:
Brain Actions: Involved in control of certain motor functions |
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Serotonin
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Location:
Brain and Spinal cord Action: May be involved in mental functions, circadian rythyms and sleep and wakefulness |
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Gamma-aminobutyric acid
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Location:
Brain and spinal cord Action: INHIBITS various neurons |
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Glycine
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Location:
Spinal cord Action: INHIBITS various neurons |
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bouton terminal
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a buttonlike terminal enlargement of an axon that ends in relation to another neuron at a synapse.
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Nissl body
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is a large granular body found in nerve cells.
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multipolar neuron
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a type of neuron that possesses a single (usually long) axon and many dendrites, allowing for the integration of a great deal of information from other neurons. These dendritic branches can also emerge from the nerve cell body. Multipolar neurons constitute the majority of neurons in the brain.
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pseudounipolar neuron
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the dendrite conducts nerve impulses toward the cell body, and the axon conducts them away from the cell body. However, the dendrite of a pseudounipolar neuron is structurally and functionally an axon, except at its terminal part where it contacts a specialized sensory organ. When the sensory organ transduces information, it initiates an action potential that is propagated toward the cell body. Because the dendrite functions as an axon, this potential does not degrade, but reaches the axon unabated and continues toward the central nervous system.[3]
Because of the similarity between this dendrite and an axon, some authors describe the pseudounipolar neuron as having one process that leaves the cell body, an axon. The dendrites are placed "on top of" the axon, connected with the receptors |
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Bipolar neurons
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a type of neuron which has two extensions. Bipolar cells are specialized sensory neurons for the transmission of special senses. As such, they are part of the sensory pathways for smell, sight, taste, hearing and vestibular functions.
The most common examples are the bipolar cell of the retina, and the ganglia of the vestibulocochlear nerve.[1] When used without further detail, the term usually refers to the retinal cells. Bipolar cells are also found in the spinal ganglia, when the cells are in an embryonic condition. |
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Nucleus (Nervous system)
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A cluster of cell bodies WITH IN the CNS
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Ganglion (Nervous system)
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A cluster of cell bodies OUTSIDE the CNS
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Cortex
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layered arrangement of neuron cell bodies on the surface of the cerebrum and cerebellum(gray matter)
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astrocyte (CNS)
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Fibrous and protoplasmic;
They are located beteen capillary (or pia matter) and neurons and are implicated in the blood brain barrier. 80% of brain capillary surfaces are covered by perivascular end feet of astrocyctes |
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Oligodendrocytes (CNS)
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function in the myelinization of CNS
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Microglia (CNS)
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phagocytic macrophage-like cells of CNS
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Schwann cells (PNS)
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involved in myelinization of PNS axons
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Satellite cells (PNS)
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surround nerve bodies in ganglia of the PNS
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White matter
(spinal cord) |
Whitish nerve tissue, especially of the brain and spinal cord, consisting chiefly of myelinated nerve fibers.
Three masses of fibers(funiculi) dorsal funiculus lateral funiculus ventral funiculus With in each are tracts, long bundles of axon fibers |
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Gray matter
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greyish nervous tissue containing cell bodies as well as fibers; forms the cerebral cortex consisting of unmyelinated neurons
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Protection of spinal cord
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Bony vertebral column, 3 connective tissue sheaths(meninges - dura mater,arachnoid membrane and pia)
CSF is in the subarachnoid space and bathes the cord and acts as a cushion |
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Spinal Nerves
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31 pairs of spinal nerves
8 cervical 12 thorasic 5 lumbar 5 sacral 1 coccygeal Cord ends at vertebra L2 |
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Brain
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Three main parts:
1. cerebrum(2 hemispheres) 2. brain stem 3. cerebellum |
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Brain stem
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the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus
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Cerebrum (2 hemispheres)
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The large rounded structure of the brain occupying most of the cranial cavity, divided into two cerebral hemispheres that are joined at the bottom by the corpus callosum. It controls and integrates motor, sensory, and higher mental functions, such as thought, reason, emotion, and memory.
Each lobe consists of 5 lobes: 1. frontal - major motor area 2. parietal - sensory impressions such as touch, pressure, and pain 3. occipital - vision 4. temporal - hearing 5. insula - lies deep to the brain's lateral surface, within the lateral sulcus |
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Cerebellum
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The part of the vertebrate brain that is located below the cerebrum at the rear of the skull and that coordinates balance and muscle activity. In mammals, the cerebellum is made up of two connecting hemispheres that consist of a core of white matter surrounded by gray matter.
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Brainsteam Parts:
medulla oblongata |
The medulla oblongata controls autonomic functions, and relays nerve signals between the brain and spinal cord. It is also responsible for controlling several major autonomic functions of the body:
1.respiration (via dorsal respiratory group and ventral respiratory group) 2.blood pressure 3.heart rate 4.reflex arcs 5.vomiting 6.defecation |
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Brainsteam Parts:
pons |
relays sensory information between the cerebellum and cerebrum. Aids in relaying messages in the brain, and contains the pneumotaxic centres that help regulate respiration. Also controls arousal.
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Brainstem part:
Midbrain |
Mesencephalon
Function: Controls Responses to Sight Eye Movement Pupil Dilation Body Movement Hearing Location: The mesencephalon is the most rostral portion of the brainstem. It is located between the forebrain and brainstem. Structures: The mesencephalon consists of the tectum and tegmentum. |
