Cellular microscopy 1: cell structure, division and repair Flashcards
Define ANATOMY
The branch of science concerned with the bodily structure of humans, animals and other living organisms
Define HISTOLOGY
The study of the microscopic structure of tissues
Define PHYSIOLOGY
The branch of biology concerned with the normal functions and mechanisms of living organisms and their parts
Define PATHOLOGY
The science of the cause and effects of diseases
Define HISTOPATHLOGY
The study of the change in tissue as a result of disease
What type of cell are plant cells?
Prokaryotic cells
What type of cell are animal cells?
Eukaryotic cells
What is an example of a prokaryotic cell?
Bacteria
Define EUKARYOTIC
A cell that possesses a clearly defined nucleus and lots of organelles
Define PROKARYOTIC
A single cell organism whose cell lacks a nucleus and other membrane-bound organelles. They have a flagella
Define FLAGELLA
A hairlike appendage that protrudes from the cell that provides motility
What is the cytoskeleton of a cell?
Provides the cell with structure and shape
What are the three types of cytoskeletal filaments found in eukaryotic cells?
Microfilaments, intermediate filaments, and microtubules
Define the MITOCHONDRIA
The powerhouse of the cell. Produces energy (ATP) for the cell through aerobic respiration . Contains two layers of membranes
Define the NUCLEUS
The largest cell organelle, it is the control centre of the cell and controls cell activities. Contains chromosomes
Define CHROMOSOMES
A thread like structure found in the nucleus of cells. Made of DNA, and contains the blue print for making up more cells. Can be seen under a microscope but only when replicating or otherwise active
Define NUCLEOLUS
A sub-organelle of the nucleus. A main function of the nucleolus is the production and assembly of ribosome components.
Is roughly spherical, is surrounded by a layer of condensed chromatin and contains RNA
Define RIBOSOMES
Responsible for protein synthesis. Often found attached to the rough endoplasmic reticulum
Define CHROMATIN
The material of which the chromosomes of organisms other than bacteria are composed. Consists of RNA, DNA and protein
Define the GOLGI APPARATUS/BODY
A series of flattened sacs that are involved in the modification, transport and storage of substances such as glycoproteins and enzymes. Its main job is to produce lysosomes (digestive enzymes)
Define NUCLEAR MEMBRANE
Surrounds the nucleus and regulates the exchange of material between the nucleus and the cytoplasm
Define the ROUGH ENDOPLASMIC RETICULUM
Branching membranes, with ribosomes on their surface. Concerned with the production and transport of protein
Define the SMOOTH ENDOPLASMIC RETICULUM
A branching membranous network without ribosomes present. It produces and transports lipids, phospholipids and steroids.
Cells that produce a lot of these substances (such as the ovaries, testes and skin oil glands) have an abundance of smooth endoplasmic reticulum
Define LYSOSOMES
Produces by the Golgi apparatus, they are single wall enzymes that act as the cell’s digestive system
Define VACUOLE
A cavity in a cell used to store excess water. Much more important in plant cells than in animal cells.
Define the CELL MEMBRANES
Made up of a phospholipid bilayer, they allow substances in and out of the cell
What are the three types of movement for cell substances?
Diffusion, osmosis, and active transport
Define DIFFUSION
The process of oxygen travelling from an area of high concentration to an area of low concentration. It is passive and does not require energy
Define OSMOSIS
The process by which water molecules pass through a membrane from a region of low concentration to high concentration. It is passive and does not require energy
Define ACTIVE TRANSPORT
The movement of molecules across the cell membrane from low concentration to high concentration. Assisted by enzymes and requires energy
Define CYTOPLASM
The fluid within the cells within which organelles are suspended
Define CENTROSOME
An organelle involved in cell replication. Always near the nucleus. Composed of two centrioles
Define MELANOSOMES
Intracellular organelles that cause pigmentation. Found in pigment cells in the skin and the eye
Define HAEMOSIDERIN
A form of storage iron derived from the breakdown or erythrocytes or haemoglobin
Define HAEMOGLOBIN
A protein containing iron that facilitates the transport of oxygen in red blood cells
What is the average animal cell size?
10-12 micrometers
How is haemoglobin measured?
Using a pulse-oximeter
Define PHAGOCYTOSIS
Ingestion of large particles (larger than 0.5 nanometres) such as protein or bacteria into the cell
Define PINOCYTOSIS
The intake of fluid through the cell membrane (the same method for phagocytosis)
Define ENDOCYTOSIS
The taking in of matter by a living cell by invagination of its membrane to form a vacuole. Both phagocytosis and pinocytosis are examples of endocytosis
Define EXOCYTOSIS
The expulsion of particles such as waste products through the cell membrane.
What are the two types of cell division?
Mitosis and meiosis
Define MITOSIS
The process by which most somatic cells divide. One parent cell divides into two identical daughter cells. The daughter cells have exactly the same number of chromosomes as the parent cell - they are copies.
What are the 5 stages of mitosis?
Interphase, prophase, metaphase, anaphase, telophase
Describe interphase
The cell is at rest; no division occurring. This stage precedes both mitosis and meiosis
Describe prophase of mitosis
The second stage of mitosis. The first significant stage - the chromosomes on the cell condense. The nuclear envelope around the nucleus breaks down
Describe metaphase of mitosis
The third phase of mitosis. Chromosomes line up along the middle of the cell. Chromatids are pulled away from the centromere. The mitotic spindle forms to separate duplicated chromosomes
Describe the anaphase of mitosis
The fourth stage of mitosis. The chromatids separate. They are pulled completely away from the centromere to the other side of the cell
Describe the telophase of mitosis
The cell is split down the middle to form two new cells. The chromatids become the new chromosomes of the new daughter cells
Define CYTOKINESIS
The part of the cell division process during which the cytoplasm of a cell divides into two daughter cells
What percentage of a cell’s total life cycle is comprised of mitosis?
10% of the cell’s total life cycle
How many chromosomes does a human have?
46 chromosomes; 23 pairs
Define DIPLOID CELLS
Cells that contain two complete sets of chromosomes, one from each parent. Mitosis results in diploid cells
What are the three stages of interphase?
- G1 - growth 1 phase. The cells intended for mitosis start to grow
- S phase - DNA synthesis. A complete copy of the DNA is created in the nucleus
- G2 phase - growth 2 phase. The second growth phase. The cell doubles in size.
Mitosis then follows the G2 phase
When does meiosis occur?
In reproduction, specifically in the gonads to produce ova or to produce sperm
How many cells are produced during meiosis?
4 cells are eventually produced. They are haploid cells, each with a single chromosome
What are the stages of meiosis?
It occurs in two phases, meiosis 1 and meiosis 2. It follows the same steps as mitosis
Describe the prophase of meiosis
Homologous pairs come together and genetic material cross overs can occur. This only happens in meiosis and aims to increase genetic variation.
Describe the interphase of meiosis
DNA replication occurs during the S phase (the same as mitosis). Each cell has a double diploid number of chromosomes
Describe the metaphase of meiosis
Homologous pairs arrange at the equator of the cell attached to spindle fibres produced by the centrioles. There are two rows, unlike mitosis, where there is only one
Describe the anaphase of meiosis
The spindle fibres contract and homologous chromosomes separate to opposite ends of the cell. The centromeres do not divide like they would in mitosis
Describe the telophase and cytokinesis of meiosis
Division of the cytoplasm results in two new cells which have a diploid number of chromosomes but are different from the parent cells (they may have a novel arrangement of alleles)
Describe meiosis 2
Has prophase 2, metaphase 2, anaphase 2 and telophase 2
Prophase 2 - the chromosomes remain contracted and genetic material is not replicated
Metaphase 2 - the chromosomes line up at the equator of the cell
Anaphase 2 - the spindle fibres contract the centromere divides and the chromatids are pulled apart and moved to opposite ends of the cell
Telophase 2 - Cytokinesis occurs. In the female this forms the ova and the second polar body, and in the male it forms the spermatids
What is the result of uncontrolled mitosis?
Mutations and neoplasia/tumours. The cell replicates too much and causes problems
Define HOMOLOGOUS GENES
Paired chromosomes that have the same gene sequence
Define ALLELES
Each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
What is Von Willebrand’s disease and what breed is it most prevalent in?
An inherited bleeding disorder. Most common in Doberman Pinschers
What are some examples of inherited diseases that can be tested for?
Hip and elbow scoring to determine likelihood of dysplasia
Progressive retinal atrophy
Von Willebrand’s disease
How are genetic conditions inherited?
Through the crossing over of genetic material
What does the effectiveness of healing depend on?
The site of the wound and the degree of damage
What are the three types of wound healing?
Resolution, regeneration and organisation
Describe resolution in relation to wound healing
Occurs in superficial grazes
No tissue destruction, and the tissue is able to return to its original state before the injury. Any damage will be very mild
Describe regeneration in relation to wound healing
The damaged tissue is completely replaced by proliferation of remaining cells. Effectiveness of regeneration depends on the cells involved, their ability to repair and human interventions such as dressing and cleaning. A good supply is essential at this stage or the wound could become necrotic
e.g. a granulating wound that involves mitosis
Describe organisation in relation to wound healing
The formation of scar tissue. Occurs when the tissue cannot regenerate, so the tissue heals through scar formation which is organised fibrous tissue with a large number of collagen fibres.
Tissue loses function and may be more susceptible to damage when it has scarred
What are the three types of cells that can be identified during wound healing?
Permanent cells, labile cells and stable cells
Define LABILE CELLS
Can divide and proliferate throughout life. They are continuously dividing tissues that can easily regenerate e.g. blood, lymph, epithelial
Define STABLE CELLS
Do not normally divide but can do in response to certain stimuli, and may divide following injury to the tissue. e.g. the kidney, liver, endocrine glands, bone and fibrous tissue
Define PERMANENT CELLS
Only divide during fetal growth and are incapable of regeneration. e.g. neurons, cardiac muscle/tissue and skeletal muscle ends
What are the phases of wound healing?
The inflammatory phase
The proliferative phase
The remodelling phase
Define PLATELETS
Thrombocytes. Small, colourless cell fragments in blood that form clots when vessels are damaged
Define FIBRIN
An insoluble protein produced in response to bleeding. A major component of the blood clot
Define NEUTROPHILS
A major type of white blood cell; the most abundant type of granulocyte
Define MACROPHAGES
Specialised cells involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms. They initiate inflammation by releases cytokines which activate other cells
Define EXUDATE
Fluid that leaks out of blood vessels into nearby tissues. Often from areas of inflammation.
What are the cardinal signs of inflammation?
- redness (rubor)
- swelling (turgor)
- heat (calor)
- pain (dolar)
- loss of function (laesa)
Describe the inflammatory phase
The initial inflammation. Platelets and fibrin are activated, and neutrophils (clear up bacteria and foreign material) and macrophages are attracted to the site.
A short inflammatory phase is key
Describe the proliferative phase
Triggered by macrophages and involves fibroblasts (the coordinators of wound healing), endothelial cells, and epithelial cells. The classic appearance of this stage is granulation tissue, which is highly resistant to infection due to the great blood supply.
What are the nurse’s responsibilities at the proliferative stage of wound healing?
They must correctly help to manage the wound through proper advice and care. This may be through advice on use of a buster collar, correct bandaging and correct suture material. Proliferation can be slowed by incorrect bandaging, patient interference, sutures that are too tight etc
Describe the remodelling phase
The final phase of wound healing
The scar remodels and strengthens over a period of day to weeks. The hair regrows, and the fibroblasts arrange the matrix of the scar tissue according to tension during normal function
How long should the inflammatory stage of healing last in a clean, surgical wound?
24-48 hours
When does the remodelling phase occur in a clean surgical wound?
at around day 7-10
What is the cell wall of bacteria made from?
Peptidoglycan
What is the purpose of the cell wall of bacteria?
To maintain the shape of the cell and prevent it from bursting
What is the purpose of a slime layer in bacteria?
They act as a barrier between the bacteria and the cell and prevent it from drying out
How are traits such as antibiotic resistance passed between bacteria?
Bacterial chromosomes are suspended in cytoplasm, and this allows easy passing on of traits
What are pili?
Straight, hair like appendages that help the bacteria stick to the host cell.
Sex pili pass on genetic material from bacteria to bacteria
Define PEPTIDOGLYCAN
A rigid envelope that surrounds most bacterial species. It protects again environmental stress and helps to preserve cell morphology. It is also sticky, helping the bacteria to adhere to structure in the body
What are the three basic shapes of bacteria?
Rod (bacilli)
Sphere (cocci)
Spiral (spirilla)
Describe bacilli
Cylindrical or rod shape. Very common and often are seen in urine or exudate
Describe cocci
Spherical cells. Commonly associated with GI disease
Describe spirilla
Corkscrew/spiral shaped cells. May be small and rigid or large and flexible
Describe vibrios
Curved rod cells. Associated with campylobacter and general GI disease
What is the difference in the streptococcus and staphylococcus bacteria?
Streptococcus is cocci formed in chains (e.g. strep throat)
Staphylococcus forms regular grape like structures (MRSA/MRSP)
What are some common bacterial diseases of the cat and the dog?
Rickettsia
Campylobacter
Salmonella
Leptospira
Bordetella brochisepta
Clostridium (tetani/botulinum)
Staphylococcus
Define PYODERMA
Literally ‘pus in the skin’. Not always visible pus
Describe gram negative bacteria
Red/pink coloured when stained. They have a cell wall and two membranes. They have more protection than gram positive bacteria, meaning they are harder to treat with antibiotics
Describe gram positive bacteria
Stain purple. They have a cell wall with 1 membrane and are generally quite receptive to antibiotics
Describe anaerobic bacteria
This bacteria will not grow in oxygen and instead grow deep within the body e.g. in the GI tract
Describe aerobic bacteria
These bacteria grow in oxygen e.g. salmonella or e.coli
Describe facultative bacteria
These bacteria can live with or without oxygen
Give some examples of gram positive diseases
Staphylococcus
Streptococcus
Clostridium tetani
Give some examples of gram negative diseases
Leptospira spp
Salmonella
Campylobacter
Bordetella
mycoplasma haemofelis
What is the difference between bacteriostatic and bactericidal antibiotics?
Bacteriostatic antibiotics will only prevent the bacteria from reproducing, where bactericidal antibiotics kill the bacteria
What are the 4 basic types of body tissue?
epithelial tissue, connective tissue, loose connective tissue and cartilage
Describe epithelial tissue
Provides coverings to the inner and outer surfaces of the body, with the main function of protecting whatever it coats from wear and tear. It also plays an important role in regulating the exchange of materials between parts of the body, as well as the external environment
What are the four types of epithelial tissue?
- simple squamous (1 cell thick)
- stratified squamous (many layered)
- transitional (can change shape and stretch)
- ciliated (has tiny hair-like cilia to prevent thing entering)
Describe connective tissue
Describe loose connective tissue
Describe cartilage
