Lab Flashcards
Histology
The study of tissues
Tissue
Group of similar cells performing a common activity
Organ
Group of tissues collectively performing a specific function
Organ System
Group of organs performing a major body function
Four types of Animal Tissues
Epithelial, connective, muscle, nervous
Epithelial tissue
Te covering or lining of free body surfaces, both internal and external
Epithelial Tissue Functions
Protection, absorption, secretion, lubrication, barrier
Apical or Luminal Surface
Free surface of the tissue is exposed to air (skin) or fluid (stomach)
Type of Epithelial Tissues
Simple Squamous Simple Cuboidal Simple Columnar Psuedostratified ciliated columnar Non-Keratinized stratified squamous Keratinized stratified squamous
Simple Squamous Location
Kidneys, lining of body cavities, blood vessels, lymphatic vessels, and heart. Also forms the entire wall of capillaries and the alveoli of the lungs
Simple Squamous Function
Exchange of materials by diffusion
Simple Cuboidal Location
Kidney’s Nephron Tubules
Simple Cuboidal Function
Secretion and absorption
Simple Columnar Location
Walls of villi in small intestine
Simple Columnar Function
Absorption of nutrients, secretion of digestive juices as well as secretion of mucus by goblet cells
Goblet Cells
- Oval cells scattered throughout the epithelium
- Secrete mucus into the respiratory tree
- Trap foreign material with mucus
Microvilli
increase the surface area for absorption of nutrients
What are the two types of stratified squamous epithelium
Non-Keratinized & Keratinized
Non-Keratinized (Wet) Squamous Location
Places subjected to abrasion, moist areas on the body
Oral cavity, pharynx, esophagus, vagina, and anus
Non-Keratinized (Wet) Squamous Function
Protect against abrasion and pathogens to underlying tissues
Keratinized (dry) Squamous Function
Waterproof and microbe-proof barrier
Keratinized (dry) Squamous Location
Dry surfaces, such as the surface of the skin. Composes the epidermis
Thick is found on the surface of the soles of your feet and on the surface of your palms, thin is found everywhere else on the surface of the skin of your body
Pseudostratified Ciliated Columnar Epithelium Location
Lines the nasal cavity, trachea, and bronchi
Pseudostratified Ciliated Columnar Epithelium Function
To protect structures, secrete mucus by goblet cells, and move mucus by cilia
Connective Tissue
Most widespread and abundant tissue in the human body.
Connective Tissue function
to support, anchor, and connect various parts of the body
Connective Tissue structural elements
cells, fibres, and intercellular substance
Connective Tissue Proper
encompasses all organs and body cavities connecting one part with another and, equally important, separating one group of cells from another
(areolar, adipose, and dense regular tissue)
Specialized Connective Tissue
Cartilage, bone, blood
Fibroblasts
produce fibres and other intercellular materials
Areolar (loose) connective tissue
Most widespread connective tissue of the body
Areolar (loose) connective tissue Location/ function
- to attach the skin to the underlying tissue
- fills the spaces between various organs and thus holds them in place as well as cushions and protects them
- surrounds and supports blood vessels
Adipose Connective Tissue
Characterized by a large internal fat droplet
Adipose Connective Tissue location/function
storage site for fats (lipids), also pads and protects certain organs and regions of the body. It also forms an insulating layer under the skin which helps regulate body temperature
Cartilage
Non-vascular tissue, characterized by lacunae, chondrocytes, and matrix. There are three types : hyaline, elastic, and fibro
Hyaline Cartilage locations
The skeleton of a mammalian fetus is composed of hyaline cartilage. Nasal septum, rings of trachea and bronchi, ends of ribs, and the articulating surfaces of most joints
Hyaline Cartilage Functions
provide strong yet flexible support and to reduce friction within joints
Chondrocytes
the large cartilage cells which are trapped within the matrix in spaces called lacunae
Blood
liquid extracellar matrix called plasma, which contains water, salts, proteins, glucose, lipids, glycoproteins, hormones, amino acids, and vitamins.
Erythrocytes (red blood cells)
most abundant, responsible for transport of O2, some CO2, and nutrients
Leukocytes
larger, nucleated and found in hte blood during transport. They defend the organism against bacteria, parasites, and pathogenic microorganisms such as viruses, fungi, and protists
Platelets
Small cell fragments that aid in blood clotting
Platelets function
stop the loss of blood from wounds
Muscle Tissue
Highly specialized for contactions
cells= fibres
cytoplasm = sarcoplasm
cell membrane = sarcolemma
Skeletal Muscle Tissue
Movement of the bones of the skeleton.
- voluntary muscles
- striated and cylindrical with blunt ends
Smooth Muscle Tissue
Throughout the internal organs of the body
- involuntary muscle
- not striated
- spindle cell shape
Cardiac Muscle Tissue
Restricted to wall of the heart
- involuntary
- striated
- form long chains that branch and intertwine
- intercalated disc (heavy dark line running across the fibre)
Nervous Tissue
conduct electrical impulses which allow communication among other tissue types
Neuron
composed of a cell body containing a nucleus and one or more long cytoplasmic extensions known as fibres
Dendrites
fibres of the neurons, bring impulses towards the cell body
Axon
Carries information away from the cell body
Enzyme
act as biological catalysts by accelerating chemical reactions
Substrate
Substance on which the enzyme acts
- can also be called the reactant
Product
the substance that results from the reaction
Enzyme characteristics
- they’re proteins
- each react with a specific substrate
- cannot change the equilibrium concentrations for a given reaction, however they do lower the EA
- don’t affect the free energy changes (DG) of a given reaction
- emerge unaltered from reactions ready to act again and again
Activators
chemicals that must bind for the enzyme to be active
Cofactors
non-protein substances that usually bind to the active site on the enzyme and are essential for the enzyme to work
Organic cofactors
coenzymes, but other cofactors may simpl be metal ions
Inhibitors
chemicals that interfere with enzyme activity
how to measure enzyme activity
- determine the rate of disappearance of the substrate
or - determine the rate of appearance of the product
Catechol oxidase
an enzyme present in potatoes & other plants
Catechol oxidase in the presence of O2
catalyzes the removal of electrons and hydrogens from catechol, which is then converted to benzoquinone
Benzoquinone
product of catachol oxidase and O2, responsible for the darkening of fruits and vegetables after exposure to air
(pigment product)
Competitive inhibition
structurally similar to the substrate, competes for a position at the active site on the enzyme, thereby making the enzyme unavailable to the substrate
- can be reversed if the concentration of the substrate is raised while the inhibitor’s is held constant
Noncompetitive inhibition
binds to a site that is not the active site and changes the nature of the enzyme so that its catalytic properties are lost.
-Results in inactivation, increasing the concentration of substrate will NOT reverse the inhibition
Resolution
ability to see fine detail, may be measured as the minimum distance between two points at which they are discernible as two distinct points, rather than a single point
Working distance
the distance between from the objective to the slide
Types of microscopes
compound, dissecting, electron
Condenser
concentrates light up to the specimen
Coarse adjustment
controls working distance between slide and objective lens
specimen holder knobs
move slide in the y & x axis
object stage
platform for viewing specimens on slides
parfocal microscope
allows changing magnification without refocusing
iris diaphragm
controls the amount of light emitted to the specimen
fine adjustment knob
permits depth perception of viewed object
substage illuminator
provides illumination
revolving nosepiece
supports the objective lenses and allows changing of the objective
Calculating scale
- Find the field diameter
- Linear fraction (how much of the field diamter does the object take up?)
- True diameter = (FD) x (LF)
- Scale your drawing –> Drawing diameter/ true diameter = 18mm/3.7mm
Cross section (x.s.)
cut at right angles to the longitudinal axis of an object
Longitudinal section (1.s)
cut parallel to the longitudinal axis of an object
Median section (med.)
cut along the middle of an object
Radial section
cut made along a radius of a circular object
(x.s.)
cross section
(1.s.)
longitudinal section
(med.)
median section
Prokaryotic cells
found in bacteria and blue-green algae
- absence of a nuclear membrane or a defined nucleus
- lack any internal membranous structures that are present in euk.
Eukaryotic cells
Plant and animal cells
Plant cell
large central vacuole, cell wall, chloroplasts, no centrioles
Animal cell
no chloroplasts, vacuole, or cell wall
Nucleus
control center of cell operations and contains genetic information
Mitochondria
site of cellular respiration and ATP production
Ribosome
protein synthesis
Golgi apparatus
receiving, modification, and shipment of proteins produces in rough ER or manufacturing of some macromolecules such as carbohydrates
Nucleolus
makes ribosomal subunits and synthsises rRNA
Lysosomes
contains digestive enzymes and involved in phagocytosis and autophagy
Plasma membrane
selective permeability
Cell wall
maintains cell’s shape and protects from mechanical injury
Centrioles
contribute to the formation of spindle apparatus
Cytoskeleton
retains cell’s shape, provides structural support, functions in cell movement, and allows movement within the cell
Vacuole: plants
storage of water, breakdown and storage of waste products and storage of pigments
Vacuole: animals
food vacuoles containing food products or contractile vacuoles in animal-like protists to remove excess water
Chloroplast
photosynthesis –> stroma, 3 membranes, stacked disks
Rough ER
membrane factory of the cell or makes secretory proteins (contains ribosomes)
Smooth ER
synthesis of lipids or metabolism of carbs or detoxification of drugs
Nucleotide three components
- A five carbon sugar called deoxyribose
- phophate group
- nitrogenous base (A,G,C,T)
How does replication of DNA occur
5’ to 3’ direction of a 3’ to 5’ template
Mitosis
replace dead, worn out cells, and for growth
- produces two cells that are genetically identical to each other and to the original parent cell
- contains the same chromosome complement, and the same genetic complement
Interphase
A cell that is not dividing - G1 (gap phase 1) - S (synthesis phase) - G2 (gap phase 2) individual chromosomes are not distinguishable in the nucleus and the genetic material is referred to as chromatin
G1 phase
phase occurs immediately after a cell division and is a period of intense metabolic activity resulting in cell growth and production of new cytoplasmic organelles
S phase
DNA replication occurs
- each chromosome replicates itself and becomes two sister chromatids held together by a centromere
G2 phase
this phase is short, the cell is metabolically preparing to divide
Mitosis
prophase, metaphase, anaphase, telophase
PMAT –> we got molly a PMAT when she was a puppy
Prophase
- Chromatin begins to coil and individual chromosomes begin to become distinguishable
- nuclear membrane breaks down and nucleolus begins to disappear
- spindle of microtubules forms across the cell
- condensing chromosomes become attached to spindle fibres by specialised regions of the centromeres known as kinetochores
- spindle fibres extend from the poles to the kinetochores, while continuous spindle fibres extend from pole to pole
- the complete disappearance of the nuclelus and the nuclear membrane mark the end of prophase
Metaphase
- chromosomes orient at the equator of the spindle
- once the chromosomes are attached to the spindle they are in constant motion along the spindle axis
- chromosomes move toward the central region of the spindle with their centromeres oriented on one plane (metaphase or equatorial plane)
- centromeres lie aroud the equator while the arms of the sister chromatids extend freely in any direction into the surrounding cytoplasm
Anaphase
- centromeres divide producing two seperate daughter chromosomes each with their own centromere
- daughters migrate towards opposite poles of the spindle with the centromere leading (macaroni)
- end of anaphase is marked by the arrival of all the daughter chromosomes at their respective poles
Telophase
- prophase in reverse
- chromosomes disperse and are no longer individually distinguishable since they are uncoiling and elongating
- nuclear membranes and nucleoli reappear
- spindle apparatus disintegrates
- end of telophase coincides with the division of the cytoplasm
- once telophase ends the cell enters interphase again and the cell cycle continues
cytokinesis
division of the cytoplasm
Aster
composed of astral rays, fibres radiating from each pole in all directions with their free ends lying in the cytoplasm
Cleavage furrow
cytoplasm is gradually pinched in until seperate cells are formed
Meiosis
- produce haploid cells as they contain half the number of chromosomes present in the original diploid cell
- four cells produced by meiosis do not contain identical genes
Interphase I
- Process occurs in the S phase of interphase
- as in mitosis, the chromosomes are drawn out into fine threads called chromatin and there is a definite nucleus with a nuclear membrane and nucleoli
Prophase I
- individual double-stranded chromosomes become apparent
- difference between mitosis and meiosis is the pairing of homologous chromosomes in meiosis
Synapsis
- the members of each pair of homologous chromosomes come together and lie side-by-side
- homologous chromosomes intertwine and crossing-over occurs
crossing-over
the breakage and exchange of genes between homologous chromosomes occur
Tetrad
grouping of two homologous chromosomes, each of which consists of two chromatids
Metaphase I
- chromosome is associated with spindle fibres attached to only one pole of the cell
- homologous chromosome lies beside it, attached to one spindle fibre extending the the opposite pole
- orientations of the paternal and maternal chromosomes relative to the poles are random –> this independent assortment is a source of genetic variation
Anaphase I
- There is no division of centromeres
- members of pairs of homologous chromosomes move to opposite poles
- 3 double stranded chromosomes at each pole, as opposed to chromatids in mitosis
Telophase I
- essentially the same as mitosis
- exception is that the new nuclei formed have only half as many chromosomes as were present in the parent cell
- now 2 cells each with half the original number of chromosomes
Interkinesis
- short interval between the two divisions of a complete meiotic cycle
- no replication of the genetic material
Prophase II
the pairs of chromatids shorten and coil, spindle apparatus forms and each pair of chromatids begins to attach to two spindle fibres at its centromere
Metaphase II
each pair of chromatids is attached, at its centromere, to spindle fibres from each pole. The chromatid pairs line up with their centromeres along the metaohase plane of the cell
Anaphase II
- chromatids seperate from each other as the centromeres split. The chromosomes are pulled towards opposite poles of the cell
Telophase II
- chromosomes lengthen and disperse, nuclear membranes reform
- cleavage furrow appears and cytokinesis occurs
- at the end of this stage four hapoid cells have been produced from the original diploid cell
