Week 2 - Tissues And Virus Flashcards
1
Q
3 functions of the skin
A
- assists in temp regulation
- synthesis of vitamin D. Cholesterol is converted to VitD in the skin when exposed to UV light
- protects underlying tissues from damage due to microbes, chemicals, water loss or water entry, UV light
2
Q
What layer of the skin are the sensory receptors in?
A
Dermis
3
Q
What do the mucous membranes do?
A
Line the body cavities that open to the exterior
4
Q
What do the serous membranes do?
A
Line body cavities that do not open to the exterior
5
Q
What do the visceral layers cover?
A
Covers the organs within the cavities. Eg. Heart, lungs and digestive organs
6
Q
What does the parietal layer cover?
A
The cavity walls
7
Q
Define microbiology
A
Study of organisms too small to be seen without a microscope
8
Q
Define disease
A
Infection which harms the host causing damage to cells and tissues
9
Q
Define microorganism
A
Includes bacteria, viruses, fungi, Protozoa and prions
10
Q
Define pathogen
A
A microorganism / infectious agent that causes disease
11
Q
Define Colonisation
A
Presence, growth, multiplication of an organism without observable clinical symptoms or immune reaction in a patient.
They don’t have the disease but they have the microorganism
12
Q
Define contagious
A
Infectious disease that spreads from person to person
13
Q
Define carrier
A
People with no symptoms but have the pathogens in their body and can transfer to others
14
Q
Define infection
A
Invasion of a pathogen microorganism into the tissues of a host where they multiple causing ban immune response with or without recognised symptoms
15
Q
Define symptomatic
A
Pathogen multiplies within a host and causes injury to cells or tissues, so host has clinical signs and symptoms
16
Q
Define Asymptomatic
A
A pathogen multiples within a host but does not cause injury to cells/tissue so has no signs or symptoms
17
Q
Define virulence
A
The potency of a pathogen to infect a host and cause death in the host
18
Q
Chain of infection in order
A
- infectious agent
- reservoir
- portal of exit
- mode of transmission
- portal of entry
- host
19
Q
Define reservoir
A
Habitat in which an agent can live, grow and multiply
20
Q
6 reservoir of microorganisms
A
- Humans
- Zoonoses (animals)
- Soil
- Water
- Air
- Food
21
Q
6 factors which provide the best environment for survival of a pathogen in the reservoir
A
- Warm/moist environment
- Isotonic surroundings
- Oxygen (depending on bacteria)
- Temp close to 37°C
- pH close to 7
- Availability of nutrients
22
Q
What is a fomite?
A
Materials/object likely to carry an infection
23
Q
Define portal of exit
A
Path by which a pathogen leaves the host
24
Q
6 portal of exits from humans
A
- Blood
- Broken skin
- Respiratory tract
- Anus
- Mucous membranes
- GI tract
25
Define mode of transmission
The way in which an infectious agent may be transmitted from its reservoir to the susceptible host
26
Direct contact is..
Skin-skin contact (kissing, sexual intercourse)
27
Indirect contact is..
Transfer of an infectious agent from a reservoir to a host by suspended air particles
28
Droplet is..
Spray with relatively large, short-range aerosols produced by sneezing, coughing or even talking
29
Airborne is..
Infectious agents are carried by dust or droplet nuclei suspended in air. May remain suspended in the air for long periods of times and may be blown over great distances (up to 1 metre)
30
What is a vector and how to they transmit disease?
Mosquitoes, fleas, and ticks may carry an infectious agent through purely mechanical means or may support growth or changes in the agent
31
Define portal of entry
The way a path eg on enters a susceptible host
32
Define host
Susceptibility of a host depends on genetic or constitutional factors, specific immunity and non specific factors that affect an individual’s ability to resist infection
33
What is resident (normal) flora?
Microorganisms that usually occupy a body site and do not cause disease under normal circumstances
34
8 sites resident flora can be found
1. Mouth
2. Upper respiratory tract
3. Small intestines
4. Urinary tract
5. Skin
6. Colon
7. Vagina
8. Conjunctiva
35
Describe the benefits of resident flora
- stimulate immune system
- manufacture vitamins (vitamin K for blood clotting, Vitamin B12 for manufacturing red blood cells)
- helps to inhibit growth of pathogens by providing competition for space and nutrients
36
3 places where you would NOT expect to find any resident flora
- blood
- brain
- muscle
37
What is an opportunist microorganism
Non-pathogenic microorganisms that act as a pathogen in certain circumstances
38
Define transient flora
Microorganisms that transiently colonise the skin and can be easily removed
39
What is the difference between a localised infection and a systemic infection?
- localised refers to an infection that is confined to one organ system or to one area of the body
- systemic affect several organs and tissues
40
Bacteria advantages from bio films
- cannot be easily removed
- provides nutrients
- protects against desiccation by antibiotics
- protects against changes in pH
41
Tissue types
- epithelial
- connective
- muscle
- nervous
42
Where does the epithelial tissue cover?
- body surfaces, forms glands and lines hollow organs, body cavities an ducts
43
What is the function of the epithelial tissue
- protection (epidermis on the skin)
- sensory (skin, eyes, ears)
- secretion (substances such as enzymes and hormones)
- absorption (nutrients from digestive system)
- excretion (waste products)
44
What are the functions of connective tissue?
- bind tissues together
- support and strength tissue
- protect and insulate internal organs
45
What does connective tissue include?
- ligaments:tendon/cartilage
- blood
- bone marrow
46
Type of muscle tissue
- skeletal (generates physical force to make body structures move )
- smooth (found in walls of viscera)
- cardiac (found in the wall of the myocardium)
47
Nervous tissue functions
- rapidly regulates and integrates
- detects changes in the body
- responds by generating nerve impulses
48
3 layers of the skin
- epidermis
- dermis
- hypodermis
49
Functions of the skin
- protection (prevents underlying tissue damage from microbes)
- sensory (receptors detect touch, pressure, vibration, tickle, heat, cold, and pain)
- excretion (approximately 400ml/day lost via skin)
- stores blood (blood redirected to vital organs)
- vitamin D synthesis (cholesterol converted to Vitamin D in the skin during UV exposure)
- temperature regulation (receptors detect temperature changes and the responds)
50
What layer of the skin are the sensory receptors located in?
- dermis
51
What does Keratinocytes produce?
Keratin
52
What does melanocytes produce?
Melanin
53
Function of Keratin
- protects the skin and underlying tissue from heat, microbes and chemicals
54
Function of Melanin
- contributes to skin colour and absorbs damaging ultraviolet (UV) light. Production is increased when cells are being damaged
55
Factors affecting skin colour
- Melanin (reddish-yellow to brown-black colour)
- carotene (yellow-orange pigment in carrots/pumpkin)
- haemoglobin (protein that gives red blood cells colour when fully oxygenated)
56
Age related changes
- reduced sweat production
- poor skin healing
- hair loss
- wrinkling
- blood vessel walls thicken
57
Where does hair growth start?
In the matrix
58
What is the matrix supplied with?
Supplied with capillaries that provide hormones, chemicals and nutrients to stimulate hair growth
59
How does hair grow?
- cells in the matrix divide actively
- as new cells are produced, older cells push up. Keratin increases and they fuse together when cells die
- hair grows in cycles
60
Three types of epithelial membrane
- cutaneous
- mucous
- serous
61
First line of defence
- physical and chemical barriers
62
How does the mucous membranes act as a parried to potential pathogens?
Mucous traps dust, foreign particles and microbes from entering
63
4 secretions
- lysozyme (tears, saliva, sweat)
- stomach acid (pH destroys most organisms entering the body via food and drink)
- pH (vagina in adult females)
- lactoferrin (saliva, breastmilk)
64
Where does fungi grow
- in conditions where bacteria could not survive (tinea - ringworm)
65
How does Protozoa move?
- by flagella, cilia or pseudopodia
66
How is a a prion begin
- begins as normal proteins in the plasma membrane of brain cells (eg. CJD)
67
How does helminths spread?
Often linked to poor sanitation and hygiene practices.
Enter the host by ingestion of food and water (pinworm)
68
4 stages of infection IN ORDER
- incubation period
- prodromal stage
- illness stage
- convalescence stage
69
What happens in the incubation period?
- interval between entry of pathogen to appearance of first symptoms (vary from days-weeks-months)
- pathogen is growing in numbers
- patient is infectious
70
What happens in the prodromal stage?
- interval from onset on non-specific signs (headache, malaise, lack of appetite) and symptoms to general signs and symptoms (fever, pain, inflammation)
- pathogen is growing in numbers and multiply
- patient is infectious at this time
71
What happens in the illness stage?
- phase of rapid multiplication
- signs and symptoms are disease-specific tans very pronounced
- maybe considered the acute phase
- the patient is infectious at this time
72
What happens at the convalescence stage?
- interval when acute symptoms disappear (could be days - weeks - months)
- pathogen load declining but may still be present
- patient may still be infectious at this time
73
The hypodermis consists of
- areolar and adipose tissue
74
What substance is used for protection from UV radiation?
- Melanin
75
Layer of the skin with no blood vessels?
Epidermis
76
Which layer of the skin acts as a blood reservoir
Dermis
77
The brain stops sending nerve impulses to the sweat glands when..
The core body temperature returns to normal
78
People who rarely venture outdoors or completely cover their skin when outdoors may develop a deficiency of
Vitamin D
79
Thermoreceptors cells in the skin send nerve impulses to..
- temperature control centre of the brain
80
As cells are pushed from the deeper portion of the epidermis towards the surface..
They degenerate and die
81
Where do viruses multiply?
In a living host
82
A gram-negative bacteria is responsive to treatment with penicillin
False
83
Lysozyme is an example of
An enzyme which is bacteriocidal
84
Which layer of skin is composed of connective tissue?
Dermis
85
Type of tissue that binds and supports organs and tissues is
Connective
86
Produced by the sebaceous glands to moisten and soften skin
Sebum
