BIOL121 Flashcards
(49 cards)
1
Q
What are the components of a virus?
A
- Not living
- No cellular structure
- Protein capsule around DNA or RNA
- Can mutate
- Antivirals > Antibiotics
- Size = billionths of a metre
2
Q
Components of bacteria?
A
- Prokaryote
- Mostly unicellular
- Different Shapes
- Have a cell wall (thickness is important)
3
Q
Components of Protozoa?
A
- Eukaryotic Cells
- Unicellular
- Usually motile
- Size from 1 to 150 microns (millionth of a metre)
4
Q
Components of Fungi?
A
- Eukaryotic Cells
- Multicellular
- Large (organ systems)
- Eggs / larva / adult reproduction
- Don’t proliferate host
5
Q
What range of temperature does most bacteria multiply in?
A
10-39 degrees Celcius
6
Q
What are the three types of bacterial multiplication (temperature)?
A
- Thermophile optimum (60 degrees C)
- Mesophile optimum (25-30 degrees C)
- Psychophiles (10 degrees C)
7
Q
What pH do bacteria multiply in?
A
pH 7
8
Q
What are the 3 types of bacterial multiplication (oxygen)?
A
- Obligate aerobes (Only grow in O2)
- Obligate anaerobes (Can NOT grow in O2)
- Facultative anaerobes (+/- O2)
9
Q
Components of Gram +ve bacteria?
A
- Capable of forming spores
- Reinfection +++
- Thick layer of peptidoglycan
10
Q
Components of Gram -ve?
A
- More difficult to kill
- Produces endotoxins
- Reinforces with 2nd membrane
11
Q
What is Normal Flora?
A
Microbes that are always present within a human that usually do not harm or cause diseases.
12
Q
What are the beneficial roles of Normal Flora for the skin?
A
- Reduces pH levels
- Changes environmental conditions
- Not ideal for other species
13
Q
What are the beneficial roles of Normal Flora for oral / vagina?
A
- Competes and inhibits pathogens and yeasts
14
Q
What are the beneficial roles of Normal Flora for the intestine?
A
- Excrete antibacterial chemicals
- Synthesise and secrete vitamins (esp. Vit. K)
- Stimulate local immunity (lympathic tissue, lg)
15
Q
What are the harmful effects of Normal Flora?
A
- Competition for nutrients
- Bacterial synergism: normal flora + pathogen
- Endogenous disease: fever, inflammation, ?cancer
- Opportunistic infection: overgrowth, infection
16
Q
What is Mode of Transmission?
A
It is the different ways that bacteria can move between host to host.
17
Q
What are the 5 Modes of Transmission? Explain each one briefly.
A
- Contact: is contact between people, either directly via touch or indirectly between two people touching the same inanimate object.
- Vehicle: is transmission of pathogens via vehicles such as air, water, food (COVID)
- Vector: transfer of pathogens via an animal (often arthropods like mosquitos or ticks)
- Fomite-borne: transmission via an inanimate object
- Vertical: Intrauterine, and post-partum
18
Q
Name each stage of the Chain of Infection and briefly explain each stage.
A
- Infectious Agent: What are we dealing with?
- Reservoir: Population of organisms in which the infectious agent sits.
- Portal of Entry: Site of which the infectious agent enters the patient. E.g. Mouth.
- Mode of transmission: How does it transmit from patient to patient?
- Portal of Exit: How does the infectious agent escape the patient?
- Susceptible Host: Typically patients who are more likely to develop diseases. E.g. Children, elderly, etc.
19
Q
What are the 3 types of environmental control for bacteria? Explain each one.
A
- Sterilisation - destroys and eliminates ALL microbes. E.g. heat (dry = burning, moist = boiling).
- Disinfection - destroys and eliminates MOST microbes from inanimate objects. E.g. Chemical (alcohol, chlorine).
- Sanitisation - Safe disposal of human urine and faeces.
20
Q
What are the 3 layers of the skin?
A
- Epidermis: The Outermost layer
- Dermis: The layer below the epidermis
- Hypodermis: Deep to the dermis (not considered part of the skin)
21
Q
Describe the components of the Epidermis.
A
- Outermost layer
- Composed of epithelial cells: keratinised stratified squamous epithelium.
- Thinner portion of the two
- Avascular
- no blood vessels
22
Q
Describe the components of the Dermis.
A
- Deep to the Epidermis
- Makes up the bulk of the skin
- Composed of connective tissues: mainly collagen and elastin
- Highly vascularised
- Highly innervated
23
Q
Describe the components of the Hypodermis.
A
- Subutaneous layer, not really part of the skin
- Lies beneath the Dermis
- Also called superficial fascia (band)
- Anchors the skin the the underlying structures
- Stores fat
24
Q
What are the 4 cell types in the Epidermis?
A
- Keratinocytes: most abundant, produce keratin, arise from the deepest layer of the Epidermis.
- Melanocytes: spider-shaped cells that produce melanin, found in the deepest layer of the Epidermis.
- Langerhan’s Cells: star-shaped macrophage cells, activate immune system, originate from bone marrow
- Present at the epidermis-dermis junction, associated with nerve endings, function as sensory receptors.
25
Name the layers of the Epidermis.
1. Stratum corneum - Outermost layer (what you see)
2. Stratum lucidum - intermediate layer
3. Stratum granulosum - intermediate layer
4. Stratum spinosum - intermidate layer
5. Stratum basale - Outermost layer (sits on top of the Dermis)
26
What are the two types of skin? Describe them.
1. Thick skin
- composed of all 5 layers
- covers palms, fingertips, soles of feet
2. Thin skin
- missing the stratum lucida
- all the layers are thinner than thick skin layers
- covers the rest of the body
27
What are the 4 cells types in the Dermis?
1. Fibroblasts
2. Macrophages
3. Some mast cells
4. White Blood Cells
28
What are the layers of the Dermis?
1. Papillary
- Thinner of the two layers
- Superficial to the reticular layer
sits directly underneath the Stratum basale of the Epidermis
2. Reticular
- thicker of the two layers, roughly 80% of the Dermis.
- Deep to the Papillary layer
- Lots of collagen to stop penetration
29
What are the three factors of skin?
1. Melanin
- pigment made in skin (melanocytes)
- exposure to UV increases melanin synthesis
- darker skin due to more melanin, and type of melanin produced, not more melanocytes
2. Carotene
- yellowish / orange pigment (found in carrots)
- accumulate in stratum corneum
3. Haemoglobin
- red pigment of blood
- gives fair-skinned people a pinkish hue.
30
What are the functions of the skin?
- Protection
- the skin is the most vulnerable organ in the body. It is constantly exposed to bacteria, abrasions, temperature extremes, chemicals, etc.
- Acts as 3 types of barriers:
1. Chemical barrier: skin secretions of melanin
2. Physical barrier: continuity of skin, waterproof
3. Biological barrier: Langerhan's cells, macrophages
31
What is the Lymphatic System?
The Lymphatic System is a network of vessels, tissues, and organs that help maintain fluid balance and fight infections in the body.
32
Descibe and name the roles of the Lymphatic System.
- Drains excess fluid + proteins from all tissues back to blood circulation
- Defends the body against external and internal threats (immunity/resistance to diseases)
- Transports fats and vitamins from gut to liver (digestion)
33
Describe the components of the Lymphatic System.
- Fluid connective tissue
- Contains lymphocytes and macrophages + enemies they seek out to destroy
- Foreign cells (microbes)
- Foreign proteins
- Cancer cells
- Plasma proteins + Red Blood Cell (RBC) usually not found
Flow through special tubes from tissues to the venous system and heart
- Lymphatic capillaries
- Lymphatic vessels, trunks, and ducts
34
Describe the Lymph Pathway.
Blood plasma (from capilaries) -> interstitial/tissue fluid -> lymphatic capillary -> lymph vessels, trunks, and ducts -> blood plasma (vein at the base of the neck)
35
Describe the structure and the components of the Lymphatic Capillaries.
- Capillaries that begin as blind ended tubes
- Structure similar to blood capillaries: one layer of epithelial (endothelial) cells supported by basement membrane
- Structure helps to let fluid in, but not out. Overlapping endothelial cells open when tissue fluid pressure is high (one-way valve)
- Fluid inside is called 'lymph' (contains mostly water, no plasma proteins, maybe some antibodies, etc.)
- Lymph capillaries in intestinal villi = Lacteals.
36
How do we ensure that lymph is being moved through the lymph vessels efficiently?
Although lymphatic capillaries have thin walls, they resemble veins, causing them to have more valves. They have lymph nodes at intervals that assist with filtration. Respiratory and muscular pumps promote flow of lymph towards large veins/heart.
37
What are the 2 thoracic ducts? Describe them.
1. Left Thoracic Duct - Smaller duct. Only drains right hand side of the body above the navel (right arm, right side of the chest, and right side of the head)
2. Right Thoracic Duct - Larger duct. Drains the rest of the body (left side of the upper body and the entire lower body)
Lymph from ducts flow into left and right subclavian veins.
38
What are the Primary Lymphatic Organs?
- Red Bone Marrow
- Thymus
39
What are the Secondary Lymphatic Organs?
- Spleen
- Lymph Nodes
40
What are the Diffuse Lymphatic Organs?
- Tonsils
- Adenoids
- Peyer's Patches
41
Describe Red Bone Marrow
- Typically found in flat bones and at the end of long bones
- Contains haemopoietic stem cells
- Produces and matures B-cells and makes pre T-Cells (lymphocytes)
42
Describe the Thymus Gland (in the mediastinum)
- Large in infancy
- max size (70g) at puberty
- atrophied (3g), but functional in adulthood
- T-cells mature here
- Thymus makes thymosin hormones for the development and maturation of T-cells
43
Describe Lymph Nodes
- Size 1-25mm
- Along lymphatic vessels (esp. near neck), axillae and inguinal area
- Multiply lymphocytes; "finishing school" for B-Cells
- Filter lymph: Afferent vessels bring lymph with foreign material into the node.
- Foreign matter trapped in fibres
- Destroyed by macrophages, B and T-cells
- Efferent vessel leaves node with cleaner lymph
44
Describe the Spleen
- Between stomach and diaphragm
- Macrophages remove work out or defective RBCs, WBCs, and platelets
- Stores and releases blood and blood cells
- Site of production of blood cells during the second trimester of pregnancy
45
What does MALT stand for?
mucosa-associated lymphoid tissue
46
Describe MALT
- Nodules scattered in connective tissue layer in the mucous membrane. E.g. tonsils, Peyer's patches in the small intestine, and appendix.
47
What is an antigen?
Anything capable of inducing an immune response. Anything foreign to you as the host.
48
Name 3 examples of an antigen
- microbes
- protein from other species
- transplanted tissue from other humans/animals
49
