WEEK 2 Flashcards
Define radiology.
The use of radiation (such as x-rays) or other imaging techniques (ultrasound and MRI) to diagnose or treat disease.It provides images of almost any organ, system or body part in a noninvasive way so that diagnoses can be made.
Describe the medical imaging technique of an X-ray, what does it involve? List its advantages & disadvantages.
High energy part of the EM spectrum which allows x-rays to pass through the body and reach a film (unlike light)
ADV: Good for showing trauma, joint disease, chest pathology & bowel obstructions (among other things)
DIS: High energy waves absorbed by body tissues & energy generates free radicals which can interact with genetic material causing damage
Causes an increased risk of cancer.
Describe the medical imaging technique of an CT (computer tomography), what does it involve? List its advantages & disadvantages.
How it works: D = detectors T = x-ray tube X = x-rays R = direction of rotation ADV: Lets you look in any plane. Used to stage tumours, for trauma, cerebrovascular disease, surgical emergencies etc DIS: V.v. expensive to buy AND run High radiation dose ( a CT of the abdomen/pelvis is equivalent to 400 chest x-rays)
Describe the medical imaging technique of an PET (Positron Emission Tomography), what does it involve? List its advantages & disadvantages.
HOW it works:
Principle 1 = unstable compound decays by emitting positron (animatter). Positron then hits an electron, mutual annihilation, 180 deg pulse gamma radiation
Principle 2 = Most cancers have a high rate of metabolism (main metabolic agent = glucose) Therefore, if an usntable compound is joined to a glucose molecule, it will accumulate at sites of high metabolic activity
ADV: used for staging of tumours & for detecting recurence AFTER treatment
DIS: cyclotron(mini particle accelerator), short half life, expensive £££, high dosage of radiation
Describe the medical imaging technique of an Ultrasound, what are its advantages & disadvantages?
ADV: safe, used for soft tissue detail, mainly on heart, pelvis, abdominal solid organs & obstetrics
DIS: cannot penetrate bone, the waves are scattered by air & so cannot view bowel, also solid organs may be obscured by gaseous bowel
Describe the medical imaging technique of an MRI (Magnetic Resonance Imaging), what does it involve? List its advantages & disadvantages.
A magnetic field is applied & short burst radiowaves applied at resonant frequency. Protons give up energy & this is detected to make the picture
ADV: non-ionising radiaiton, few known side-effects, wonderful soft tissue visualisation & characterisation, able to do functional studies
DIS: expensive, dangerous (metal in room or patients), noisy, pts must lie for long periods of time, claustrophobic
What are the 4 types of body tissues?
- Epithelia
- Connective tissues
- Muscle
- Neural tissues
Describe the characteristics of epithelia.
Functions in: secretion, absorption, transport, as a barrier & for strength/support
Covers surfaces but have varied shape & arrangement (flat, cube, columned, multilayered)
Are bound to each other by specialised junctions & adhesion molecules
Sit of the BM - which contains proteins that link to the surface of epithelial cells, they also contain filament proteins which provide strength
What is the function of (i) Microvilli (ii) Cilia
(i) Contain actin, for absorption/sensing
(ii) contains microtubules for movement/lateral transport
What are the 4 main types of junctions? What are their functions?
- Tight junctions = sealing
- Desmosomes = strengthen cell links
- Gap junctions = connect cytosols of adjacent cells for v.small molecules
- Adherens junctions = spots of actin (connection linking movement protein)
Describe the characteristics of nervous tissue. (i) What is a neuron (ii) What is the function of an axon (iii) What is the function of dendrites?
(i) Separate cells that communicate by releasing chemicals by secretion at the ends of cell processes
(ii) Direct stimulus AWAY from the cell
(iii) Direct stimulus TOWARDS the cell
What are the 4 types of glial cells of the CNS? Describe their function.
- Oligodendrocytes - myelination, one cell builds a number of internodes
- Astocytes “star cells” - metabolic & mechanical support. Contribute to scar formation
- Microglia - come from blood, essentially macrophages
- Ependyma - lining cells of CNS cavities
What are the 2 types of glial cells of the PNS?
- Schwann cells - myelination
2. Satellite cells - support cells in ganglia
What are the 3 types of muscle cells? What do cardiac cells contain for strength?
- Skeletal
- Cardiac
- Smooth
Cardiac cells contain ionic coupling (i.e. gap junctions) for strength
What is connective tissue?
A mix of different cells & ECM (which contains fibrous proteins, structural carbohydrates & proteins mineral deposit
What is the function of (a) Fibroblasts (b) Macrophages (c) Mast cells (d) Plasma cells?
(a) synthesise fibrous proteins
(b) Phagocytose foreign bodies/organisms. Present antigens to stimulate immune cells
(c) synthesise histamine & other inflammatory mediators
(d) Synthesise antibodies (mature B cells)
Describe the role of (i) White fat (ii) Brown fat.
(i) stores energy BUT is extremely dynamic. Produces adipokines which send signals to regulate nutritional balance. E.g. leptin sends signals to the brain that the body has “had enough to eat”
(ii) Makes heat by uncoupling oxidative phosphorylation in mitochondria. Conters hypothermia in babies & is located in the upper trunk region.
What is the function of epithelial tissue?
It covers all external & internal body surfaces & forms boundaries between body compartments
What separates epithelial cells from the underlying connective tissue? Describe it.
Basement Membrane
- thin sheet composed of collagen & glycoprotein. Produced partly by epithelial cells & partly by underlying connective tissue cells
For simple squamous epithelium, (i) How many layers is it made up of (ii) What is the shape of the cells (iii) Give examples.
(i) 1 Layer
(ii) Flattened, plate like
(iii) Lining of body cavities, lining of capillaries & BVs
For simple cuboidal epithelium, (i) How many layers is it made up of (ii) What is the shape of the cells (iii) Give examples.
(i) 1 Layer
(ii) Approx same height & width
(iii) Secretion & absorption in the liver & kidneys
For simple columnar epithelium, (i) How many layers is it made up of (ii) What is the shape of the cells (iii) Give examples.
(i) 1 Layer
(ii) Approx twice as tall as wide
(iii) Secretion & absorption in the GI tract
For pseudostratified epithelium, (i) How many layers is it made up of (ii) What is the shape of the cells (iii) Give examples.
(i) 1 Layer
(ii) Appears like 2 layers as some cells are short & others tall
(iii) Respiratory epithelium lines conducting part of the airway