Phase 1

Question 1

Name 4 functions of skin

Answer 1

1. Water Repellent
2. Immunological Barrier
3. Mechanical Barrier
4. Sensation
5. Synthesis of Vit D
6. UV Protection

Question 2

Describe the structure of skin

Answer 2

Three Layers; epidermis, dermis, subcutis.

Epidermis (Avascular)

• Stratum (Keratinocytes)
• Stratum Lucidum
• Stratum Granulosum
• Stratum Spinosum
• Stratum (Merkel Cells)
• Basement Membrane (Type IV Collagen)

Dermis
- Papillary Layer
Areolar tissue, connective tissue that contains dermal papilla from epidermis. Meissners Corpuscles - Light Touch.

• Reticular Layer
  Dense and irregular, contains most accessory structures. Pacinan Corpuscles for deep pressure and vibration.

Subcutis
- Adipocyte rich. Padding. Vascularised.

Question 3

Describe the main difference between thick and thin skin.

Answer 3

Stratum Lucidum exists on palms and soles of the feet. Thin layers do not contain these layers.

Question 4

Name the cell types found in the epidermis and state their function.

Answer 4

1. Keratinocytes - 95% of cells in the epidermis. Produces keratin.
2. Melanocytes - produce melanin for UV protection. Transfer via projectins.
3. Langerhans Cells - DCs, APC.
4. Merkel Cells - Mechanoreceptors

Question 5

Name the layers of the epidermis.

Answer 5

Epidermis (Strata Corneum, Lucidum, Granulosum,

Question 6

Describe the role of skin the synthesis of Vit D

Answer 6

UVB photons are absorbed to convert 7-dehydrocholesterol to previtamin D3.

Question 7

Describe the cell junction between the epidermis and the dermis and a pathology associated with it.

Answer 7

Epidermis and the dermis is joined at the dermo-epidermo junction by the interactions of Retes Ridges in the papillary layer. Hemi-desmosomes bind intermediate filaments and Focal Adhesions bind Actin Filaments.

Pathology is Epidermolysis Bullosa simplex.

Question 8

Name the layers of the dermis

Answer 8

Papillary (superficial) and reticular (deep)

Question 9

State 3 types of glands found in the dermis and name their function.

Answer 9

1. Eccrine Glands - produce sweat
2. Apocrine Glands - Scent
3. Sebaceous Glands - lubricant of the hair shaft

Question 10

Describe the accessory structures found in the dermis.

Answer 10

1. Eccrine Glands - produce sweat
2. Apocrine Glands - Scent
3. Sebaceous Glands - lubricant of the hair shaft
4. Meissners Corpuscles - Light Touch
5. Pacinian Corpuscles - Deep Pressure

Question 11

State the functions of the subcutaneous layer

Answer 11

1. Fat storage, energy reserve

2. Padding

Question 12

Name the type of collagen found in the skins and basement membrane

Answer 12

Skin - Type I

Basement Membrane - Type IV

Question 13

Label the diagram (layers of the skin)

Answer 13

Epidermis
- Strata Corneum, Lucidum, Granulosum, Spinosum, Basale, Basement Membrane

Dermis

• Papillary
• Reticular

Subcutis

Adnexal structures

• Eccrine, Appocrine, Sebaceous glands
• Meissner and Pacinian Corpuscles

Question 14

Describe superficial and deep wound healing

Answer 14

Superficial wound healing -

A scrape or graze, no involvement of the basement membrane. Mitotically active keratinocytes in the Basale lose BM adhesions. Migrate in leap frog or train method to form granulation tissue. Epidermal Growth Factor is released.
Basale Layer keratinocytes undergo terminal differentiation to restore lost cells.

Deep

Inflammatory phase
1. Coagulation/ haemostasis
2. Platelets secrete growth factors. WBCs are recruited. Inflammation takes place to allow vasopermeability to increase.
3. Neutrophils and Macrophages phagocytose waste. More growth factors.
(VEG-F, EGF, APF, PDGF, FGF)

Proliferative phase

1. Basement membrane is reformed and keratinocytes migrate over wound to form granulation tissue (leap frog or train).
2. Once formed, divide and differentiate. Granulation tissue laid down, mainly Type 3 Collagen.
3. Neo-vascularisation

Remodelling phase

1. Granulation tissue tissue matures to scar tissue.
2. Type 3 collagen is crossed linked, swapped for type 1. More tensile strength.

Question 15

Name three growth factors secreted by phagocytosis

Answer 15

1. Vascular Endothelial Growth Factor (VEG-F)
2. Angiogenesis Promoting Factor (APF)
3. Platelet Derived Growth Factor (PDGF)
4. Fibroblast Growth Factor (FGF)

Question 16

Name the two methods by which re-epithelialisation takes place and give a brief description of each.

Answer 16

1. Train method - a lead cell pulls following keratinocytes

2. Leap from - cells leap over one another over the wound base. Much like leap frogging or pepper potting.

Question 17

Name the cell that produces collagen.

Answer 17

Fibroblasts

Question 18

Give the effects of UV radiation

Answer 18

1. Photoageing
2. DNA Damage
3. Carcinogenesis

Question 19

Name the organelles and state their function

Answer 19

1. Plasma Membrane
   - Barrier to the outside environment, hosts receptors for signalling, mediates diffusion, holds other membrane receptors and channels.
2. Mitochondrion
   - The power house of the cell (Aerobic Respiration) producing ATP.
3. Nucleus
   - Contains the genome and is the site of transcription.
4. Rough Endoplasmic Reticulum.
   - Hosts ribosomes for mRNA translation.
5. Smooth Endoplasmic Reticulum
   - Calcium Store and lipid synthesis.
6. Golgi Apparatus
   - “Sorting office” - responsible for post-translational modifications to proteins and packaging.
7. Lysosomes, Peroxisomes and Proteasomes.

Enzymatic degradation of lipids (L), oxidative reactions/ biosynthesis of bile/ fatty acid metabolism and detox (Perox), protein degradation (Proteasome).

Question 20

What pathologies are associated with: 
A. Mitochondrial Damage
B. Defective Lysosomes
C. Microtubule Defects
D. Failure of Cell-ECM junctions
E. Connexin 26 Mutation

Answer 20

A. Damage causes the release of cytochrome C, which activate caspases, resulting in a proteolytic cascade activating DNAases, Lamin degradation and cell apoptosis. - Diabetes and Deafness (DaD).
B. Lipid build up. Neural damage. - Tay Sachs Disease.
C. Defects in dyneins in Axonemes. Leads to defunct cilia and flagellum. - Kartageners Syndrome.
D. Loss of Hemidesmosome - Intermediate Filament interaction. - Epidermolysis Bullosa Simplex.
E. Defunct connexins, leads to hearing loss.

Question 21

Describe the Cell-Cell and Cell-ECM junctions and the cytoskeleton involved.

Answer 21

Cell-Cell

1. Desmosomes - Intermediate Filaments
2. Adherens - Actin Filaments
3. Tight Junctions - Actin Filaments
4. Gap Junctions - Connexin Channels

Cell-ECM

1. Hemi-Desmosomes - Intermediate Filaments
2. Focal Adhesions - Actin Filaments

Question 22

Describe the cytoskeleton

Answer 22

A network of proteins, three types.

Microtubules, made of tubulin. Allow for push (kinesins) and pull (dyneins), these Microtubules grow and shrink from centrosomes. Allow for chromosome separation in Mitosis or movement in axonemes (cilia and flagellum).

Microfilaments made up of Actin and Myosin. Dynamic processes, such as cell shape and motility.

Intermediate filaments made up of vimentin and keratin. Provide tensile, rope like strength.

Question 23

Describe the default secretory pathway.

Answer 23

Transcription (Nucleus), Translation (Ribosome).

Signal Recognition Particle on mRNA attaches SRP-Receptor, anchoring it and ribosome to RER. Protein is translated into the ER lumen. Signal pepsidase cleaves the protein. Transportation to the Golgi Apparatus, via the Cis-Cisterna model, is sent to the plasma membrane in vesicles. Where it is modified at the C-Terminus, it is anchored to the plasma membrane.

Proteins for the lysosome are modified with mannose-6-phosphate.

Question 24

Describe the default cytosolic pathway.

Answer 24

Without SRP, the protein is translated into the cytosol.

Here, if destined for the Nucleus, the protein is modified with a Nucleus Translocation Signal (NLS)- moves via importing through the nuclear pore.

Mitochondrion proteins are modified with Mitochondrion Translocation Signal.

Peroxisomal proteins are modified at the C-Terminus with a three amino acid chain.

Question 25

Describe Lysosomal degradation

Answer 25

Cytosolic proteins are taken to the vesicle by autophagy (from the ER - mannose-6-phosphate cleaved at low pH), while extracellular components are taken in by endocytosis (surface proteins) or receptor-mediated endocytosis. An acidid pH, proteases, lipases and DNAases finish the task.

Question 26

Describe proteosomal degradation.

Answer 26

Proteins for destruction are ubiquitilated. Useful for short-half life proteins, defective proteins and those key in metabolism. Proteins are then cleaved by proteases and pepsidases.

Question 27

Define: a. genome b. proteome c. transcriptome

Answer 27

a. All genetic material of an organism b. All proteins translated from the transcriptome c. All mRNA transcribed from Genome

Question 28

Why is the proteome larger than the genome?

Answer 28

1. Alternative mRNA splicing 2. Post translational modification (Gene splicing and epigenetics?)

Question 29

Describe translation

Answer 29

DNA is transcribed to mRNA in the nucleus. The mRNA attaches to a tRNA via start codon AUG. tRNA anti-codon binds and pre-initiation complex binds small sub unit of the ribosome. Translation is initiation, working from the 5' to 3', cessation at stop codon (varies).

Question 30

Describe three post-translational modifications

Answer 30

1. Methylation - addition of a methyl group. Example is Histone methylation in gene expression. 2. Ubiquitination - addition of ubiquitin to a protein. Example is in proteosomal degradation 3. Phosphorylation - addition of a phosphate. Example is phosphorylation of myosin in muscle contraction.

Question 31

Outline the functions of blood

Answer 31

1. Transport of gases (o2 and co2), plasma proteins, hormones and of waste such as urea and uric acid. 2. Homeostasis - buffer of pH, restriction of flui loss. 3. Immunity by WBCs.

Question 32

Describe the composition of blood

Answer 32

1. Plasma 55% - Plasma Proteins 7% (Albumin, Globulins, Fibrinogens) - Solutes 1% (Ions, organic waste such as urea) - Organic nutrients like lipids, amino acids. - Water 92% 2. Haematocrit 45% - Erythrocytes 99.9% - Leukocytes 0.5% - Platelets 0.5%

Question 33

Name the different plasma proteins and their function

Answer 33

1. Albumins - Osmotic Pressure - Transport protein (such as lipids and billirubin) 2. Globulins - Transport of ions, lipids, hormones - Immunoglobulins in immunity 3. Fibrinogen - Coagulation, Haemostasis Others, such as hormones (insulin), zymogens, coagulation factors.

Question 34

Name the cell types found in blood and state their function.

Answer 34

1. Erythrocytes - Carriage of o2 and co2. 2. Leukocytes - Innate and Adaptive Immunity 3. Platelets - Not technically cells. Coagulation, haemostasis.

Question 35

Describe a RBC

Answer 35

1. Also called erythrocytes 2. Biconcave in shape, allows flexibility 3. Anucleated with no organelles, allowing extra capacity for haemoglobin 4. Life span of 120 days 5. Contains molecules of haemoglobin, accounts for red colour 6. Low energy demand 7. Carriage of o2 and co2 (Binds haemoglobin)

Question 36

Describe the platelet

Answer 36

1. Not a cell 2. Cell fragments (Megakaryocyte) 3. Small 4. Principle role in coagulation/ haemostasis 5. Short life span 9-12 days 6. Anucleated, no organelles

Question 37

Describe the different WBCs and state whether their origin is lymphoid or myeloid.

Answer 37

1. Neutrophil - Myeloid - Most common at 65% - Multi-lobed nucleus - granule rich - Innate 2. Lymphocytes - Lymphoid - 2nd most common at 30% - Large nucleus occupies most of the cytoplasm - Differentiates into, T, B and NK types for adaptive immunity. 3. Monocyte - Myeloid - Differentiates to Macrophage - Kidney shaped nucleus (bilobe) - 3rd most common - 8% 4. Eosinophils - Myeloid - Red in colour, acidophillic. - Bilobed nucleus - Granule rich, cytotoxic. - Fight parasites - Innate - 4th most common, 4.5% 5. Basophils - Blue, basic. - Highly granulated - Role in allergy - less that 1%

Question 38

List the WBCs in order of abundance

Answer 38

1. Neutrophil 2. Lymphocyte 3. Monocyte 4. Eosinophil 5. Basophil

Question 39

Describe the triage system and the role of the triage nurse

Answer 39

Triage, french for "sieve", is a system used to prioritise patients for treatment based on medical urgency. It is commonly used in pre-hospital, A&E and military settings. It is dynamic and changes with assessment. Multiple systems exist. In the UK, A&E's commonly use the Manchester System defining categories as: 1. Immediate (, MI) 2. Very Urgent, 10 mins (Chest pain) 3. Urgent, 1 hour (poison) 4. Standard, 2 hours (minor injury) 5. Non-urgent, 4 hours (non-acute) The triage nurse will monitor patients, carry out obs, bloods, ECGs and aid the the triage picture. Dependant on Trust.

Question 40

Define shock and list five types.

Answer 40

Shock is the loss of circulating blood, causing inadequate perfusion of body tissue impairing metabolic function. 1. Hypovolemic - A bleed - Loss of sodium causing dehydration 2. Cardiogenic - Acute M.I reduced cardiac output 3. Septic - Systemic inflammation causing vessels to become "leaky". Fluid migrates to tissues. 4. Anaphylactic - Allergy, inappropriate inflammation causing leakage. 5. Spinal - Injury causing loss of sympathetic innervation and decrease in vasomotor tone leading to hypotension (C.O cannot match compliance).

Question 41

Define differentiation

Answer 41

The process by which a cell matures and specialises through regulated gene expression.

Question 42

# Define the terms: 1. Totipotent 2. Pluripotent 3. Multipotent 4. Unipotent

Answer 42

Totipotent - can differentiate into all cell types. Zygote. Pluripotent - can differentiate into most cell types - blastocyst. Multipotent - progenitor cell able to differentiate into many cell types. Unipotent - able to mature into one cell type, such as erythroblasts.

Question 43

Describe haematopoeisis and discuss it’s regulation.

Answer 43

1. Is the production of blood cells from Haematopoeitic Stem Cells (HSCs) in the bone marrow. 2. HSCs can differentiate into Myeloid and Lymphoid stem cells. 3. Lymphoid Stem Cells are directed by normal control originating in the Thymus. Pre-T-Cells migrate to the Thymus to undergo selection, while Pre-B/ NK cells remain in the Bone Marrow these are acted upon by IL-7. 4. Common Myeloid Progenitor cells give rise to erythroblasts (stimulated by EPO), megakaryocytes (TPO) and select leukocytes (IL-3, IL-6m GM-CSF). GM-CSF plays a large role in all cell types of Myeloid lineage.

Question 44

Outline the possible fates of a stem cell.

Answer 44

1. Self Renewal 2. Quiescence 3. Apoptosis 4. Differentiation

Question 45

Compare adult and embryonic stems cells.

Answer 45

(You’ll have to touch on ethics here, too) Adult Stem Cells - Less ethical issues - Difficult to culture - Less potent - Useful for transplants - Multipotent at best Embryonic - Highly emotive topic, ethical maze - Easy to culture - High potency - Risk of rejection - Pluripotent

Question 46

Describe the process of haemostasis and coagulation

Answer 46

1. The arrest of blood loss. 2. Vascular phase - local vasospasm reduces blood flow. - Basement membrane collagen is exposed. - Damaged endothelial cells release Endothelins (promotes growth and repair and vasoconstriction). - Tissue Factor to initiate Extrinsic Coagulation. - NO balance is upset with tissue damage, prostacyclin released. - Endothelial cells become “sticky” 3. Platelet phase - Platelets stick to exposed collagen and endothelial cells. - Platelets release granules on binding. vWF facilitates early binding and aggregation. Released in granules are: ADP, TxA2 and serotonin. - Bound platelets express Glycoproteins II/IIb - Prostacyclins keep this +be feedback loop in check. - This primary haemostasis plug is formed. 4. Coagulation - Initiated at the extrinsic pathway (tissue factor - PT time assesses this). - Tissue Factor III(3) activates VII (7) to VIIa (7a). - These combine to form TF-VIIa (3-7a). - This in turn activates X to Xa (10 - 10a) - Concomitant with the intrinsic pathway (contact activation). - XII (12) is activated to XIIa (12a). - XI (11)is activated to (11a) - IX (9) is activated to IXa (9a) - X is activated to Xa (10 - 10a) Xa marks the convergence to the Common Coagulation Pathway. Xa is activated in the presence of Ca and Pl. - Prothrombin II (2) is activated to Thrombin IIa (2a) by Va and Xa. - IIa activates V (5) to Va (5a) and Fibrinogen I (1) to Fibrin Ia (1a). XIIIa (Fibrin stabilising) helps cross link Ia. The stable Fibrin Clot is formed. 5. Clot lysis - by Plasmin - TF is inhibited by TFPI - Protein C inhibits lots of Fs. - Antithrombin. Think.

Question 47

Describe the basic structure of bacteria and their function.

Answer 47

1. Cell Wall - A polysaccharide layer, protective. 2. Plasma Membrane - phospholipids. Boundary of the cytosol. 3. Plasmids - Short fragments of DNA that can be exchanged. With other CFUs. 4. Mesosomes - Folded invagination of the cell wall, increasing surface area. 5. Chromosomes - Genetic material, as with eukaryotic cells. 6. Ribosomes - for protein translation 7. Flagellum - for motility 8. Pili - Hairlike appendages. Allow for adherence, can also be used in conjugation (sex pili).

Question 48

State the different shapes of bacteria

Answer 48

1. Cocci - Single (Coccus), double (diplococci) or bunched (cocci) 2. Bacilli - Rod like 3. Coccobacilli - Round rod, like a rugby ball. 4. Spirochetes - Spiral in structure.

Question 49

Define the terms Gram Positive and Gram Negative in microbiology.

Answer 49

Gram Positive (Gram +ve). - Stains well in “Gram Stain”. Due to a thick peptidoglycan wall. ``` Gram Negative (Gram -ve) Stains poorly due to a thinner peptidoglycan wall. Usually has outer layer/ capsule holding LPS and endotoxins. Bad times. ```

Question 50

Describe two key differences between gram +ve / -ve

Answer 50

+ve stains rich in Gram Stain, think peptidoglycan wall. -ve stains poorly, thin peptidoglycan wall and hosts outer layer rich in LPS and Endotoxins.

Question 51

Name two of each: 1. Gram -ve Bacilli 2. Gram -ve Cocci 3. Gram +ve Bacilli 4. Gram +ve Cocci

Answer 51

1. E.coli and S.enterrica 2. N.meningitidis and H.Influenzae 3. C.Dificile and L.monocytogenes 4. Staph.aureus and Strep.aureus

Question 52

# Define: 1. Endotoxin | 2. Exotoxin

Answer 52

1. Endotoxins: a bad time. Structures found on the outer layer of gram -ve bacteria. Can be shed. Common example is LPS. 2. Secreted (not shed) by bacteria, disrupting cellular metabolism

Question 53

Describe basic viral structure.

Answer 53

1. Genetic material that comes in a variety of flavours. - Double or Single stranded DNA (dsDNA/ssDNA) - Double or Single stranded RNA (dsRNA/ssRNA) 2. Capsid. Viral protein coat made up of capsomeres. 3. Some contain basic enzymes, such as reverse transcriptase.

Question 54

Describe the shapes of nucleocapsids

Answer 54

Viral. Icosahedral. 20 triangular shapes organised to form a coat. Helical. Rod shaped and filamentous. Prolate. Sophisticated is shape. A cylinder flanked by two caps. Bacteriophages.

Question 55

Describe the process of viral replication

Answer 55

1. Absorption. The virus binds to a specific receptor. Such as HIV binding CD4 CCR5. 2. Penetration. The viral coat fuses with the cell or is endocytosed. 3. Uncoating. The viral capsid is lost, free nucleic acid is in host cytosol. 4. The coup etat. Host cell metabolism halts. Viral nucleic acid is transcribed and translated using host cell organelles. 5. Synthesis. Viral genome is replicated. 6. Assembly. Viral products are assembled, capsomeres self-assemble around viral genome to form new virions. 7. Release. Virions either bud from the host cell, or cause cell lysis. 8. The virus spreads.

Question 56

State the primary and secondary lymphoid glands.

Answer 56

a. Primary. Where lymphocytes are produced and mature; Bone marrow and Thymus. b. Secondary. Where lymphocytes migrate to undergo clonal expansion. Lymph nodes.

Question 57

Describe how lymph is formed.

Answer 57

Blood arrives to the capillary bed at high hydrostatic pressure. Fluid, minus haematocrit is force through capillary gaps. As blood moves along the capillary, fluid returns due to osmotic pressure. Remaining fluid in the tissues is the lymph. It is returned to circulation via the right and left venous angle.

Question 58

State 4 functions of Lymph

Answer 58

1. Transport of lipids, fat and chyle 2. Removal of excess fluid, preventing oedema 3. Transport of APCs and Antigens to initiate the adaptive immune response 4. Maintenance and distribution of lymphocytes.

Question 59

Describe lymphopoeisis

Answer 59

Haematopoeitic Stem Cell, which is multipotent differentiates into either Myeloid or Lymphoid Stem Cells. Lymphoid Cells remain in the bone marrow, or migrate to the Thymus. Thymus cells undergo selection, and can be induced by APCs, while B and NK cells are influence into growth by IL-7.

Question 60

Describe Lymph flow through a lymph node.

Answer 60

1. Afferent lymphatic 2. Subscapular space and cortical sinus 3. Through the deep cortex and germinal centres. 4. Through the paracortical area 5. Through medullary cords in the medulla and out via the efferent lymphatic.

Question 61

List (label) the parts of the lymph node, and the cell type prominent in each zone.

Answer 61

1. Afferent Lymphatics 2. Germinal Centres - B CELLS (proliferate and mature) 3. Cortex - B CELLS 4. Paracortical area - T Cells 5. Medulla - Macrophages and Plasma Cells. 6. Afferent Lymphatics

Question 62

Describe Innate Immunity

Answer 62

1. Physical Barriers - The skin, and other epithelial linings. - Secretions can support these barriers, such as sweat on the skin or secretion of mucus in the airways. A variable pH in the alimentary tract also acts to eliminate microbes. - Immunoglobulins in secretions (IgA in saliva) 2. Associated Lymphoid Tissues - around epithelial linings, such as the Peyers patches (GALT). Rich in immunoglobulins. 3. Innate line leukocytes - Monocytes, Neutrophils, Dendritic Cells (phagocytic) * These act as APCs, presenting to T Helper Cells. * Recognise Pathogen Associated Molecular Patterns (PAMPs) and Damage AMPs via Toll Like Receptors (TLRs). Eg. TLR-4 Recognises -ve LPS. 4. Immune surveillance - Natural Killer Cells “ID Check” via MHC-I. Kill any self-cells that have gone awry (viral or cancerous). 5. Interleukins and Interferons (Cytokines) - Soluble proteins. Broad usage. Such as IL-6, pyrogenic or IFN-Y, increases MHC-II expression and M.O recruitment. 6. Complement - Opsonisation, Inflammation, Lysis. A cascade of proteins. Three pathways. Classical, Alternative and Lectin. C3a kick starts it all (such as by binding Fc Ab). 7. Inflammation Palor, Rubor, Dolor, Tumor, Functio Laesa 8. Fever IL-1 and IL-6 encourage the release of prostaglandins in the hypothalamus, increasing core body temperature, off setting ideal growth environment for pathogens.

Question 63

Explain the concept of PAMPs and TLRs

Answer 63

PAMPs, Pathogen Associated Molecular Patterns, are highly conserved components of pathogens. These components are fundamental to the pathogens function, so is usually expressed. They are detected by Toll Like Receptors (TLRs) on host Leukocytes. Example: Lipopolysaccharide (LPS) on -ve bacteria are detected by TLR-4.

Question 64

Name five pro-inflammatory cytokines

Answer 64

1. IL-1 - pyrogen 2. IL-6 Pyrogen 3. TNF-A - Vasopermability 4. IL-8 - Chemoattractant of neutrophils 5. IFN-Y - stimulates Macrophages (IL-12 - Activates NK Cells)

Question 65

Describe the physical barriers of the body

Answer 65

1. Epithelium 2. Mucous Membranes 3. Secretions 4. Ear wax 5. Hair in the nose and ears 6. Tears

Question 66

Describe the MHC and which cells they are found on.

Answer 66

MHC Class I, found on all nucleases cells. Present self antigen to NK Cells and Tc Cells. Made of three alpha and 1 beta2 chains. MHC Class II - Found on Antigen Presenting Cells (in abundance on professional APCs). Present ingested, non-self antigen to Th Cells. 2 alpha and 2 beta chains.

Question 67

Name the three pathways of the complement system.

Answer 67

1. Classical Pathway (Adaptive, C3a is activated by Ab Fc) 2. Alternative Pathway (C3 binds the pathogen) 3. Lectin Pathway (fungi and parasites)

Question 68

Give three functions of the complement system

Answer 68

1. Inflammation. Anaphylatoxins formed during cleavage are responsible. 2. Opsonisation, another component of cleaved proteins. “Tag” microbes for more effective killing. 3. Lysis. The terminal sequence of complement by the formation of the Membrane Attack Complex (MAC).

Question 69

What is the equation for the activation of C3a?

Answer 69

C3 ——- C3a via C3 Convertase (C3bBb or C4bC2a)

Question 70

Explain how NK Cells kill.

Answer 70

Natural position is to kill other cells, bind MHC-I. If non-self/ aberrant/ absent antigen is presented, the cell is killed by performing and granzymes.

Question 71

State the functions of the Interferons

Answer 71

Alpha - produced by infected cells. Chemoattractant for NK Cells and phagocytes. Beta - Produced by infected cells to stimulate anti-viral proteins in non-infected cells. Gamma - Produced by T Cells to stimulate macrophages. (Also expression of MHC-II).

Question 72

State the cardinal signs of inflammation, and how they are produced.

Answer 72

Rubor - Redness. Increased vasodilation Tumor - Growth. Increased vasopermeability. Dolor - Pain. Stretching of tissue. Calor - Heat. Fever and blood flow. Functio Laesa - Loss of Function, due to swelling. Restrictive and protective.

Question 73

Describe the process of leukocyte extravasation.

Answer 73

1. Chemoattraction - cytokines cause endothelial cells to express selectins. Leukocytes slow down due to vasodilation. 2. Margination and Rolling Adhesion - Leukocytes bind selectins via integrins. Rolling and slowing. 3. Tight Binding. 4. Diapedesis. “Foot through” of Leukocyte through junctions between endothelial cells. 5. The cell fully migrates.

Question 74

Describe Adaptive Immunity

Answer 74

Active: - Natural (Infection) or Artificial (Vaccine). Passive: - Natural (gaining Abs from mother breastmilk or across the placenta.) - Active (vaccine). Antigen Presentation. More traditional. 1. Carried out by Professional Antigen Presenting Cells (APCs) or standard APCs via Major Histocompatibility Complex Class II (MHC-II) 2. APCs or free antigen travel to the lymph nodes via the afferent Lymphatics. 3. Antigen is presented to CD4+ Lymphocytes (Th Cells). 4. Th Cells are co-stimulated by adnexal receptors and activated. (B7 APC - CD28 ThC) 5. Cytokines IL-2, IL-6 facilitate this. 6. Cells undergo Clonal Expansion. The differentiation of cells to target the same epitope. 7. T Cells act similarly, but react via MHC-I. 8. B Cells mediate the humoral (antibody) response while T Cells either help, or facilitate the cell mediate response (cytotoxicity.)

Question 75

Describe the five classes of antibody.

Answer 75

IgM - A pentamer. Binds a broad range of epitopes. IgA - Dimer, found often at Lymphoid Associated Tissues. IgD - Membrane bound, used as a receptor. IgG - Highly specific binding. IgE - Role not really known, targets parasites and helminths. Role in allergy.

Question 76

Draw and label an IgG molecule.

Answer 76

1. Two long chains 2. Two short chains 3. Joined by disulphides bonds. 4. Variable, antigen binding site/ region. “Fab” 5. Constant region “Fc”.

Question 77

What is the function of IgE?

Answer 77

Allergy. Mast Cell degranulation.

Question 78

Give five functions of antibodies.

Answer 78

1. Opsonisation 2. Complement Activation 3. Neutralisation 4. Agglutination 5. Attract phagocytes

Question 79

Define the term Neoplasia

Answer 79

A new abnormal growth, occurs due to unregulated cell proliferation.

Question 80

Define the term Tumour

Answer 80

A growth of the same neoplasm.

Question 81

Define the term Cancer

Answer 81

A neoplasia that has metastasised.

Question 82

Define the term Cell proliferation

Answer 82

Cell division and reproduction

Question 83

Define the term Apoptosis

Answer 83

Programmed cell death

Question 84

Define the term hyperplasia

Answer 84

Increase in cell number, causing an increase in tissue size. Often early sign of neoplasia.

Question 85

Define the term dysplasia

Answer 85

Abnormal growth/ organisation of a tissue

Question 86

Define the term metaplasia

Answer 86

A tissue has differentiated into another tissue type/ mimics another tissue type.

Question 87

Define the term Benign

Answer 87

A tumour that does not metastasise.

Question 88

Define the term Malignant

Answer 88

A tumour which has invaded or metastasised. Gives rise to secondary tumours.

Question 89

Define the term hypertrophy

Answer 89

Increase in cell size, causing increased tissue size.

Question 90

Define the term labile

Answer 90

Not stable. Rapid cell turnover

Question 91

Define the term stable

Answer 91

Not labile. Slow cell turn over.

Question 92

Define the term permanent (cells)

Answer 92

No cell turn over

Question 93

Define the term cell cycle

Answer 93

The interval between two mitotic divisions resulting in two daughter cells.

Question 94

Describe the four phases of the cell cycle.

Answer 94

“Interphase” - G1 phase. Mitogen dependant. The cell grows in size, proteins are synthesised. - S phase. DNA is synthesised. - G2 phase. Cell grows, organelles are replicated. Mitosis/ M Phase. Prophase, (Pro)metaphase, Metaphase, Anasphase, Telophase, cytokinesis.

Question 95

Describe regulation of the cell cycle.

Answer 95

The four checkpoints to be revised in MBChB 1 are: Restriction Point G1/S Checkpoint G2/M Checkpoint Metaphase Checkpoint The restriction point: 1. Most important apparently. 2. A mitogen stimulates a Receptor Tyrosine Kinase, which activated the Ras pathway. (The phosphorylation of Rb, unblocking E2F.) 3. Without this, the cell will Diverge to G0 (quiescence). G1/S and G2/M Checkpoints. 1. Checks for DNA damage. P53 is active where DNA damage is detected. This activates P21, which prevents Cyclin E and A binding CDK 2. Metaphase Checkpoint. 1. Check for spindle attachment to chromatids. If improper attachment is detected, CDK 1 remains phosphorylated. 2. If all is well, CDK 1 binds Cyclin B. *Cyclin B awaits CDK 1 to bind. Cyclin B is present from G2 in anticipation. CDK1/CYCB is named in some papers as Maturation Promoting Factor (MPF). Allows for destructed of the nuclear envelope, chromatin condensation, spindle formation.

Question 96

Explain Hydrophobic Cell Signalling and examples of hormones involved.

Answer 96

The signal passes through the plasma membrane, acting on cytosolic receptors. Receptor-signal complex forms the transcription factor. Gene expression is altered, protein is translated and the effect is achieved. Example: testosterone.

Question 97

Give three reasons why cell signalling should be studied

Answer 97

1. It forms the basis of pharmacology. 2. Elucidates cellular pathways and processes. 3. Allows for the study and understanding on key hallmarks of disease.

Question 98

Explain the problems hydrophilic signalling molecules face and how this is overcome.

Answer 98

These signal molecules cannot cross the plasma membrane. Instead they bind cell surface receptors and activate a signal transduction pathway/ cascade. This then leads to an inter-cellular response.

Question 99

Describe G-Protein Coupled Receptors.

Answer 99

1. Serpentine in shape, with 7 transmembrane domains, starting at an extracellular binding site. 2. Ligation causes a conformational change at the intracellular domain, where a G-Protein binds. 3. GDP is swapped for GTP on the G-Protein. 4. The G-Protein splits into alpha and beta subunits. 5. Beta affects ion channels, Alpha has three principle targets. - Adenylyl Cyclase which increases the production of Cyclic AMP from ATP. Binds Protein Kinase A (PKA). PKA moves to phosphorylation L-Type Calcium Channels, CREB and Phosphorylase Kinase. - Phospholipase C. Acts on IP3 and DAG. IP3 acts on the ER. DAG on Protein Kinase C. - Other G-Proteins An example is Adrenaline and Cyclic AMP.

Question 100

Describe enzyme linked receptors.

Answer 100

Principle steps. Example with Receptor Tyrosine Kinase. 1. Ligand binds with two monomers, causing dimerisation. 2. The dimer is autophosphorylated. 3. Phospho-tyrosine residues in the cytosol act as binding sites for intracellular proteins. 4. The signal is transduced. Example is FGFR3

Question 101

Describe Ion Channels.

Answer 101

Five principle steps. 1. Ligation at one of several binding sites, as the channel is multimeric. 2. Conformational change takes place. Classic. 3. Central pore is now open. 4. Ions passively diffuse. 5. Shape is maintained when ligand is bound. Example is ACH-R.

Question 102

Name two signalling molecules that bind GPCRs, RTKs and Ion Channels.

Answer 102

1. Adrenaline and Glucagon 2. PDGF and FGF 3. GABA and ACH

Question 103

Define the term Tumour Suppressor Gene.

Answer 103

A gene which, when transcribed, produces a protein that inhibits tumour growth by suppressing the cell cycle until repair or apoptosis can take place.

Question 104

Define the term Proto-Oncogene.

Answer 104

A normal functional gene that translates to a protein in normal metabolism, regulating cell cycle and differentiation.

Question 105

Define the term oncogene

Answer 105

A mutated Proto-oncogene, which is now abberantly expressed. This causes inappropriate expression of a protein and cell behaviour (malignancy).

Question 106

Describe the term mutation.

Answer 106

A change in genetic mutation.

Question 107

Describe the term activating mutation.

Answer 107

A mutation that activates an established oncogene.

Question 108

Give examples of mutations.

Answer 108

Deletion - deletion of nucleotides from a sequence, can cause a frame shift. Point Mutation - A mutation of a single base pair. Substitution - A base pair is swapped for another Chromosomal Rearrangement - portion of a chromosome swaps with another. Such as Philadelphia Chromosome (BCR-ABL). Over expression of proteins, such as in BCR-ABL, causing over signalling. Another example is where TKR is formed as a dimer, in achondroplasia. Look this up.

Question 109

Give an example of a tumour suppressor gene and explain how it works.

Answer 109

“Brakes on the cell cycle” 1. Retinoblastoma. Binds and inhibits E2F, halting the cell cycle at the restriction point. 2. P53. Activated when DNA damage is detected. Will induce apoptosis in high concentrations, in low concentrations will activate P21, which inhibits CDK2 binding Cyclin A and E, so repair can take place.

Question 110

Describe how telomeres prevent over proliferation of cells.

Answer 110

Chromosomes/ DNA have a tail of telomere, which is added by the enzyme telomerase. Typically, at each cell division this tail shortens, indicating life expectancy of the cell. When the tail is depleted, the chromosomes inappropriately fuse. This is detected as an aberrant genome and the cell is killed. Mutations in telomerases can result in immortal cells, as the tail is constantly renewed.

Question 111

Describe the Philadelphia translocation.

Answer 111

Occurs in a reciprocal translocation between Chromosome 22 and 9. The breakpoint is part way through the BCR gene on C22, fusing with (part) of the ABL gene on C9, forming the “always on” BCR-ABL gene. The product is a RTK that is active without ligation. Found commonly in Chronic Myeloid Leukaemia.

Question 112

Describe loss of TSG function.

Answer 112

It is the loss of the “brakes” of the cell cycle. Without these genes and their proteins, such as P53, DNA damage goes unrepaired and accumulates. This contributes to the multi-hit model of Carcinogenesis.

Question 113

Explain the constraints faced but tumours and how they are overcome.

Answer 113

A. Neoplastic growth can often outgrow existing vascular supply, so must increase it’s angiogenic potential to perfume it’s growth. This is facilitated with mutation and the over expression of growth factors such as vascular endothelial growth factor. This is a hallmark of cancer. B. Tumours can be confined to their original tissue, but can invade with the expression of matrix metallo proteases, breaking through basement membranes and penetrating adnexal tissues. This facilitates metastasis. C. Metastatic cancer cells can express E-Catherin, allowing them to move within tissues. Other hall marks of cancer.

Question 114

Describe Magnetic Resonance Imaging.

Answer 114

1. Protons align with or against a really big magnet. 2. Protons that align against the magnet have a higher energy level, creating an energy difference. 3. Radio waves are fired at low energy protons which excites them to a high energy state. 4. As they return to a low energy state, they will emit radio waves at the same wavelength as absorbed. 5. This is detected and data is plotted into an image. 6. Dyes and contrast can be used. 7. Well expensive 8. Low radiation though. 9. Always in high demand. 10. Good for soft tissue. 11. Great detail.

Question 115

Describe X-Rays

Answer 115

1. Electrons are emitted from a heated cathode to an anode. 2. These elections “knock” electrons in the anodes a high energy state. As they lower, they emit X-Ray radiation. 3. This is detected in a black and white image. Black representing air, white is bone while soft tissues appear a light grey. 4. Quick and inexpensive. 5. Easy 6. Good for bones, chest exams. 7. Easy to access. Dyes can be used. 8. High radiation.

Question 116

Describe CT scans

Answer 116

Circular X-Ray. Multiple X-Rays are taken, and constructed into a 3D image. Computer Tomography. High radiation.

Question 117

Describe the pathophysiology of Osteoarthritis (OA).

Answer 117

A degenerative disease of the bones and joints. 1. Can have a gradual onset by the gradual loss of articular cartilage at synovial joints, or can be the result of trauma. 2. Initially, an increase in water content is seen. 3. Proteoglycan synthesis drops 4. Aggregate, hyaluronic acid lowers in concentration. 5. Cytokines IL-1 and TNF are released in response to tissue damage. 6. Synovium inflames. 7. Neutrophils migrate to the joint and release matrix metallo proteases and collagenases. The articular cartilage is damage further. 8. Joint space reduces. 9. Subchondral sclrerosis occurs. 10. Wearing of the bone forms subchondral cysts (fluid filled sacs). 11. Osteophyte formation.

Question 118

Define Osteoarthritis

Answer 118

A progressive, degenerative disorder of the joints caused by a loss of articular cartilage and subsequent damage to joint tissues.

Question 119

Describe common joints affected by Osteoarthritis

Answer 119

1. Weight bearing joints (knees) 2. Carpometacarpal joint. 3. DIP and PIP

Question 120

Describe common changes seems in Osteoarthritis

Answer 120

1. Loss of joint space 2. Subchondral sclerosis 3. Subchondral cysts 4. Osteophytes 5. Trendelenberg sign.

Question 121

Give diagnostic techniques and symptoms of Osteoarthritis

Answer 121

``` A. X-Ray to asses bone health, joint space, osteophytes. B. Local Pain C. Joint Mobilisation D. Trendelenburg Sign. E. Occupational History F. Morning Sickness G. Crepitations ```

Question 122

Describe the Aetiology of Osteoarthritis

Answer 122

1. Primary (idiopathic). - Degenerative. 2. Secondary (of other disease) Trauma, hip dysplasia, inflammation.

Question 123

Give the risk factors and treatments of Osteoarthritis

Answer 123

Risk factors - Modifiable 1. Nutrition 2. Weight (obesity) 3. Exercise 4. Muscle Weakness - Non modifiable 1. Age Gender - men under 50, women over 50 (genetics?). Treatments - surgical 1. Arthroplasty 2. Arthroscopic repair 3. Microfracturing of subchondral bone to promote healing 4. Cartilage transplant Non-surgical 1. Walking aids 2. NSAIDS 3. Corticosteroids 4. Analgesics 5. Physio 6. Weight loss

Question 124

Describe the Skeletal Muscle

Answer 124

1. Multinucleated 2. Striated 3. Contractions are voluntary. 4. Variable speeds of contraction, fast. 5. Regenerative potential if damaged.

Question 125

Describe Smooth Muscle

Answer 125

1. Mononuclear 2. Non-striated 3. Mostly involuntary contractions - hormones and the ANS. 4. Organised around organs or vessel walls. 5. Slow contractions.

Question 126

Describe Cardiac Muscle

Answer 126

1. 1-5 nuclei 2. Semi-striated, Y-Shaped organisation. 3. Involuntary contractions 4. Connected by inter-calated discs for conductivity. 5. Medium contraction speed. 6. Independent pace set.

Question 127

Define the term Excitable Cell

Answer 127

A cell with a resting membrane potential and are electrically excitable.

Question 128

Define the term Resting Potential

Answer 128

The potential difference in charge across a plasma membrane.

Question 129

Describe the displacement of ions across the membrane.

Answer 129

Generally, there are more sodium ions on the outside of the cell, while the cytosol is rich in potassium ions.

Question 130

Describe excitation of a neurone and skeletal muscle cell. - flash card answer is poor.

Answer 130

1. Neutron resting potential sits at -70Mv, while Skeletal Muscle is around -85Mv. 2. A neurotransmitter binds and opens a Ligand Gated Sodium Channel causing Depolarisation. 3. Depolarisation must reach threshold (-55 in neurones and -60 in skeletal muscles) for an Action Potential to be created. 4. The cell then hyperpolarises returning to resting potential, enforcing a unidirectional AP.

Question 131

Describe the structure of skeletal muscle

Answer 131

Micro anatomy - 1. Epimysium surrounds the perimysium. 2. Perimysium is contains fascicles, blood vessels and nerves. 3. Fascicles contain individual muscle fibres, lower muscle neurones, myosatellite cells and the endomysium. This is best learnt by looking at a diagram. 4. Highly vascularised. The muscle fibre found in fascicles is made up of Actin (thing) and Myosin (Thick filaments). Organised into sarcomeres - 1. I Band -a region containing only thin filaments. Bisected by the Z Line and spans between the A bands. 2. Z Line - the boundary of the sarcomere. Titin extends from the top of the actin filament to the Z- Line to anchor. 3. A Band - the region of overlap between thin and thick filaments 4. M Line - the centre of the A band. Central to the thick filaments. 5. H Band - thick filaments, no thin.

Question 132

Describe the mechanism by which muscle contraction occurs.

Answer 132

1. The action potential arrives at the axonal terminal. 2. Calcium ions diffuse into the axonal terminal. The terminal releases vesicles of Acetylcholine (ACh). 3. ACh diffuses across the Neuromuscular Cleft and ligates with ACh-Receptor (nicotinic cholinergic). Ion channels open, sodium diffuses into the Sarcoplasm. 4. Acetylcholinesterase breaks down ACh. 5. Influx of sodium propagates down the Sarcolemma to the T-Tubules. 6. This causes L-Type Calcium Channels of the Sarcoplasmis Reticulum to release Calcium. - 7. Calcium binds Troponin 8. Troponin denatures and moves, exposing actin binding sites to myosin 9. The myosin head binds. ADP is swapped for ATP. 10. Power stroke, the muscle contracts. 11. Myosin head cocks back, hydrolysing ATP to ADP + H. Myosin detaches. 12. Tropomyosin covers the binding site and the muscle relaxes. 13. Calcium is pumped back into the Sarcoplasmic Reticulum.

Question 133

Define the term ECM

Answer 133

Extracellular Matrix is a network of proteins and polysaccharides secreted by cells to provide structural support and create a supportive extracellular environment.

Question 134

State the function of ECM.

Answer 134

1. Structural Support 2. Tensile Strength 3. Sequester Growth Factors 4. Provide a route for cellular migration 5. Transmission of force 6. Anchors cells (structure)

Question 135

Describe the composition and components of ECM.

Answer 135

1. Collagen - Provides tensile strength - Helical structure - Gly-X-Y repeating units 2. Elastin - Elastic properties, allows the structure to retain its shape after change. 3. Ground Substance - Water - Proteoglycans - Aggrecan - Glycosaminoglycans - Glycoproteins

Question 136

Name four different types of Collagen and where they are found.

Answer 136

1. Type I - tendons, skin, bone, ligaments 2. Type II - Cartilage 3. Type III - with Type I, especially in wound healing. 4. Type IV - Basement Membrane

Question 137

Describe the Basement Membrane

Answer 137

Three layers. Lamina Lucida Lamina Densa Lamina Fibrireticularis Rich in Type IV Collagen. 5 Functions: - Support - Allows for nutrient diffusion - Binds epithelium of underlying tissue - Path for migration in wound healing (re-epithelialisation) - Barrier preventing down growth

Question 138

Give examples of fibrous joints

Answer 138

Suture joints in the skull, gomphosis in teeth.

Question 139

Give examples of cartilaginous joints.

Answer 139

Pubic symphysis and joints between intervertebral discs.

Question 140

Give types of synovial joints

Answer 140

1. Plane 2. Pivot 3. Hinge 4. Condyloid 5. Saddle 6. Ball and Socket

Question 141

Describe the cells of the nervous system and their functions

Answer 141

A. Neurones - transmission of action potentials. 1. Uni, bi and multipolar. B. Glia (support) Cells. 1. Schwann Cells - support and form myelin sheaths over PNS neurones 2. Oligodendrocytes - support and form myelin sheaths over CNS neurones. 3. Microglia - Phagocytic cells 4. Ependyma Cell - Secretes CSF 5. Astrocytes - Nutritional Support of the CNS

Question 142

What cells secrete Cerebrospinal Fluid?

Answer 142

Ependyma Cells

Question 143

Describe the organisation of the nervous system.

Answer 143

Central Nervous System - The Brain - The Brain Stem - Spinal Cord ``` Peripheral Nervous System - Spinal Nerves A. 8 Cervical B. 12 Thoracic C. 5 Lumbar D. 5 Sacral E. 1 Coccygeal F. 12 pairs ```

Question 144

What is the function of the Frontal Lobe of the brain?

Answer 144

Higher order thinking, conscious though and memory

Question 145

What is the function of the Occipital Lobe?

Answer 145

Visual data processing

Question 146

What is the function of the Parietal Lobe?

Answer 146

Integration of sensory input

Question 147

What is the function of the Temporal Lobe?

Answer 147

Primary auditory cortex.

Question 148

Name the 12 cranial nerves

Answer 148

1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear 9. Glossopharyngeal 10. Vagus 11. (Spinal) Accessory 12. Hypoglossal

Question 149

What are the types of hypersensitivity?

Answer 149

Type I - Allergy/ Immediate - Asthma Type II - Cytotoxic/ Antibody Dependant - Thrombocytopenia Type III - Immune Complex Disease - Rheumatoid Arthritis Type IV - Delayed type. Cell mediated. - Coeliac Disease Type V - Autoimmune - Grave's Disease

Question 150

Briefly DASPITE Asthma

Answer 150

Definition: a Type I hypersensitivity disorder causing chronic inflammation and reversible restriction of the airway. Aetiology: Extrinsic/ Atopic - genetic/ environmental. Allergy, IgE mediated. FHx. Intrinsic - adult onset/ occupational. Cold weather, bronchitis. Medications such as B Blockers. Signs and Symptoms: 1. Wheezing 2. S.O.B 3. Tight chest Pathophysiology: 1. Inappropriate response to a stimuli such as allergen. 2. IgE recognise the allergen. 3. Bound IgE ligates with Mast Cells via their Fc portion. 4. Mast Cells degranulate. 5. - Histamine increases vascular permeability. (Oedema) - Leukotrienes cause smooth muscle contraction (constriction) - Prostaglandins increase vasodilation - Proteases damage and irritate tissues. (Remodelling) 6. Extravasation of WBCs - CD4+, Eosinophils, Macrophages. 7. Hypertrophy of smooth muscle cells, angiogenesis and collagen deposits. 8. Necrosis occurs where angiogenesis is insufficient. Investigations: 1. FHx 2. FEV1 3. S&S Treatments: 1. Bronchodilators - Adrenoreceptor Agonists A. Short Acting B2 Agonists (SABAS) binds B2-RSIGS and upregulates Cyclic AMP. - bronchodilation. Salbutamol B. Long Acting B2 Agonists (LABAs). - As SABAs. Salmetrol. 2. Anti-Muscarinic. A- Short Acting. Block cholinergic receptors (parasympathetic) to inhibit contractions. Ipratropium. B. Long Acting. As above. - Tiotropium. 3. Glucocorticoids - antagonists of Leukotrienes. Xanthines. 4. Theophylline - reduces airway responsiveness to histamines. ``` Order of use: SABA SABA + Steroids SABA + LABA + Steroids SABA + LABA + Steroids +/-Xanthine ``` Epidemiology: Increasing worldwide. Hygiene hypothesis has been suggested. 1/11 children and 1/12 adults in UK.

Question 151

Describe the Autonomic Nervous System.

Answer 151

Control of smooth muscle, physiological homeostasis, efferent fibres of the visceral NS. Split into two divisions. Sympathetic- 1. T1-L2, following the ventral spinal route. Principle Neurotransmitters: Adrenaline (Beta and Alpha), Noradrenaline (Alpha and Beta). ``` Receptors: Beta 1: Heart, Renal, Adrenal Glands Beta 2: Airways and Lungs Alpha 1: Arteries Alpha 2: Veins, coronary vasculature. ``` Variations: ACh in peripheral vessels and sweat glands. Nitrous Oxide works as a vasodilator. Functions: Fight or Flight. Parasympathetic. Carniosacral route. ``` Cranial Nerves: CNIII -Oculomotor CNVII -Facial CNIX -Glossopharyngeal CNX -Vagus ``` Sacral S2-S4. Receptors Muscarinic: smooth muscle cells and salivary glands Nicotinic: Skeletal muscle. Functions: Rest and Digest. Sexual arousal.

Question 152

Describe the cough reflex.

Answer 152

Innate autonomic reflex to expel irritants or clear the airway. Afferent nerve fibres from the vagus nerve provides sensory input to the medulla oblongata. Efferent signals sent via the lower motor neurones of the respiratory muscles. Phrenic - diagphragm. Laryngeal - larynx. Production of the cough. 1. Efferent nerves to the diaphragm and internal intercostals undergo a deep contraction, drawing air in. 2. Laryngeal nerve closes the glottis. Expiratory muscles contract. 3. High intrathoracic pressure and a rapid opening of the glottis causes a violent expiration.

Question 153

Describe vasovagal syncope and the first aid response.

Answer 153

A faint caused by a sudden drop of blood pressure caused by inappropriate peripheral vasodilation. Loss of sympathetic inner vat ion/ increase in parasympathetic. Contractility, heart rate and cardiac output decrease, peripheral compliance increase. Aetiology/ risk factors. 1. Stress 2. Intense pain 3. Heat injury 4. Dehydration Symptoms: 1. Light headedness. 2. Loss of sight 3. Tinnitus 4. Nausea 5. Sweating 6. Pale/ cold skin 7. Slow pulse First aid: 1. Secure the area 2. Lie the patient down 3. Treat bleeds 4. Elevate the legs 5. Recovery position if required.

Question 154

Describe the histology of the GI tract.

Answer 154

Starts at the mouth stops at the butthole ``` Histology of the GI tract. So many. - 4 layers 1. Mucosa A. Epithelium. Squamous. B. Lamina. Areolar connective tissue, C. Muscularis mucosa. Smooth muscle. ``` 2. Submucosa. Areolar tissue that binds the mucosa. Vascular. Secretions. 3. Muscularis propria. Skeletal muscle and under voluntary control. Not continuous. Lower portions contain smooth muscle. 4. Serosa. Simple squamous epithelium. Superficial

Question 155

Describe the mouth (GI Tract Organ).

Answer 155

1. Mouth - the opening of the G.I tract. - buccal cavity at cheeks. Hard palate, soft palate, tongue. - mastication and digestion with saliva.

Question 156

Describe the pharynx (GI Tract Organ) - this one is very short.

Answer 156

2. Pharynx - skeletal muscle. - pass into oesophagus.

Question 157

Describe the oesophagus (GI Tract Organ)

Answer 157

3. Oesophagus. - muscular tube. - movement by peristalsis. - non-keratinised squamous epithelium. - passes oesophageal hiatus of the diaphragm at T10. - top third - striated - mid third - mix - lower third smooth. - two sphincters. Upper (pharynx) and lower (gastro-oesophageal. Prevents acid reflux).

Question 158

Describe the stomach (GI Tract organ)

Answer 158

4. Stomach. - major digestive organ - J shaped. - mix food and gastric secretions - anatomically found in the epigastric/ left hypochondriac regions. Four sections - fungus, cardia, body and pylorus. Cells 1. Endocrine cells - gastrin 2. Chief cells - pepsinogen and gastric lipase 3. Parietal cells - HCL and intrinsic factor 4. Mucous neck cells - mucous

Question 159

Describe the duodenum (GI Tract organ)

Answer 159

Small intestine. Four parts 1. Superior - joined by the hepatoduedenal ligament. - relieves chyme 2. Descending - major duodenal papilla. Surrounded by sphincter of oddi. 3. Inferior - travels laterally to the aorta and IVC. 4. Ascending - duodenaljejunal flexure. Brunners glands secrete alkaline mucous. Pancreatic and hepatic secretions are received here. Ampulla of Vater - pancreatic and common bile duct. Cells: - absorptive cells. Brush border - goblet cells. Produce mucous. - granular cells. Produce enzymes - endocrine cells. Produce hormones.

Question 160

Describe the Jejunum (GI Tract organ)

Answer 160

Digestion and absorption

Question 161

Describe the Ileum (GI Tract organ)

Answer 161

Absorption of bile salts, Vit B12.

Question 162

Describe the colon (GI Tract organ)

Answer 162

5 parts. 1. Caecum and appendix. 2. Ascending 3. Transverse 4. Descending 5. Sigmoid Absorbs water, electrolytes, vitamin K. Stores and transports faecal matters. Gut flora. Aids in immunity, digestion and production of vitamins. Taenia coli - incomplete layer of longtitudal muscle Haustrations - ring like circular muscles.

Question 163

Describe the rectum (GI Tract organ).

Answer 163

Starts after the sigmoid colon. Five parts. 1. Sacral flexure 2. Anorectal flexure 3. Superior flexure 4. Intermediate 5. Inferior

Question 164

Describe the anal canal (GI Tract organ)

Answer 164

Two sphincters. Internal (upper 2/3), smooth muscle External (lower 1/3), striated.

Question 165

Describe the salivary glands of the GI Tract

Answer 165

Salivary glands. Submandibular - sublingual - parotid. - induction of thirst - stores fats and digests carbohydrates (alpha amylase and lingual lipases)

Question 166

Describe the pancreas

Answer 166

Digestive (exocrine) and hormonal (endocrine) functions. Retroperitoneal. Secretions out of the pancreatic duct. ``` 99% of secretions are exocrine. Contain: (Pancreatic) 1. Amylase 2. Lipase 3. Digestive enzymes 4. DNAases 5. Salts 6. Sodium bicarbonate 7. Water ``` Endocrine secretions - 1. Alpha Cells: glucagon 2. Beta Cells: Insulin 3. Delta Cells: Somatostatin

Question 167

Describe the liver (GI Tract organ)

Answer 167

Four lobes- 1. Left 2. Right 3. Quadrate 4. Caudate Functions: 1. metabolism such as conjugation of proteins 2. storage of glucagon 3. inactivation of drugs (P450) 4. production of clotting factors 5. cholesterol storage 6. production of bile

Question 168

Describe the gall bladder (GI Tract organ)

Answer 168

Location: peritoneal cavity. Right hypochondrium. Posterior to the liver. Functions- 1. Stores bile 2. Release of bile Via the common bile duct, merges with the pancreatic duct and secretes through the sphincter of oddi.

Question 169

Name the functions of the alimentary canal

Answer 169

1. Take in 2. Digest 3. Absorb 4. Expel

Question 170

Name the three salivary glands

Answer 170

1. Sublingual 2. Submandibular 3. Parotid

Question 171

Name five functions of saliva

Answer 171

1. Carbohydrate and fat digestion 2. Induction of thirst 3. Lubrication 4. Hosts IgA. 5. Moistens mouth for speech

Question 172

What region of the abdomen is the liver found?

Answer 172

Right hypochondrium and epigastrum.

Question 173

What region of the abdomen is the caecum found?

Answer 173

Right Iliac fossa.

Question 174

Name the parts of the stomach.

Answer 174

1. Fundus 2. Cardia 3. Body 4. Pylorus

Question 175

Name the cell types found in the stomach.

Answer 175

1. Endocrine cell - gastrin 2. Chief cells - pepsinogen 3. Parietal cells - intrinsic factor and HCL 4. Mucous neck cells - mucous

Question 176

List the structures that make up the small and large intestine.

Answer 176

1. Duodenum - superior - descending - inferior - ascending 2. Jejunum 3. Ileum 4. Colon - caecum - ascending - hepatic flexure - transverse - splenic flexure - descending - sigmoid (Haustrations and taenia coli)

Question 177

Describe Binary fission

Answer 177

1. Replicate the genome 2. Chromosomal segregation 3. Cytokinesis

Question 178

What are the immune privileged sites?

Answer 178

1. Eyes (not conjunctiva) 2. Blood 3. CNS 4. Inner ear 5. Middle ear 6. Sinuses

Question 179

Name the functions of the pancreas

Answer 179

``` Exocrine: (Pancreatic) 1. Amylase 2. Lipase 3. Digestive enzymes 4. DNAases 5. Salts (bicarbonate, makes it alkaline) 6. Water ``` Endocrine (langerhans cells): 1. Alpha: glucagon 2. Beta: insulin 3. Delta: somatostatin

Question 180

Name the functions of the liver

Answer 180

1. Inactivation of drugs and hormones. 2. Metabolism and conjugation of wast 3. Storage of glycogen and release of glucose 4. Platelet production 5. Production of clotting factors 6. Storage of cholesterol 7. Production of bile acid and alkaline fluid

Question 181

Describe the digestion of carbohydrates.

Answer 181

1. Begins in the mouth 2. Salivary alpha amylase produced acini cells digests 1-4 glycosidic bonds. 3. Glycogen —-> maltose 4. Bolus enters the stomach, chyme enters the duodenum 5. Pancreatic amylase in the duodenum breaks 1-4 G bonds again. Brush border enzymes: - lactase - lactose= glucose and galactose - Maltase - maltose= glucose - sucrase - sucrose= glucose

Question 182

Describe digestion of proteins.

Answer 182

1. Starts in the stomach 2. HCL from parietal cells cleaves pepsinogen to pepsin. 3. Pepsin converts proteins into polypeptides. 4. HCL works to break peptide bonds 5. In the duodenum - pancreatic and bile secretions contain proteolytic enzymes. - trypsin (first enzyme, starts cascade) - elastase - chymotrypsin - carboxypeptidase

Question 183

Describe the digestion of fats.

Answer 183

1. Begins in the mouth 2. Salivary lipase. 3. Moves as bolus to stomach - gastric lipase. 4. Most takes place in the duodenum. 5. Bile emulsifies the fat. Triglycerides become monoglycerides. 6. Fats are packaged into micelles 7. Fats are absorbed by microvilli. 8. Fats are converted back into triglycerides and aggregate with cholesterol, proteins and phosphopholipids to form chylomicrons. 9. Chylomicrons are taken up by the lymph.

Question 184

Describe the absorption of carbohydrates

Answer 184

Happens along the brush border. Can be passive, facilitated or active. Glucose and galactose - facilitated diffusion with Na co transporters Fructose - facilitated diffusion

Question 185

Describe the absorption of amino acids

Answer 185

Along the brush border. Active transport Facilitated diffusion with Na co transporters

Question 186

Describe the absorption of peptides

Answer 186

Along the brush border. Facilitated diffusion with H+ co transporter.

Question 187

Describe the absorption of fatty acids

Answer 187

Along the diffusion. Short chain - simple diffusion Long chain and 2-monoglyceride - 1. Simple diffusion in micelles (converted to chylomicrons).

Question 188

Define metabolism

Answer 188

The sum of all reactions in the body that produce energy, and where energy is then used.

Question 189

What is “energy” needed for in the body?

Answer 189

1. Maintenance of membrane potentials 2. Muscle contraction 3. Movement 4. Active processes 5. Disposal of wastage 6. Generation of heat 7. Biosynthesis Energy is stored as ATP and hydrolysed to ADP + Pi.

Question 190

Name the methods by which ATP is produced.

Answer 190

1. Creatine phosphate 2. Anaerobic respiration 3. Aerobic respiration 4. Lipolysis

Question 191

What are the outputs of the Kreb Cycle?

Answer 191

1. Two ATP 2. 6 NADH 3. 2 FADH2

Question 192

Describe the electron transport chain.

Answer 192

In the cristae of the mitochondria. The site of oxidative phosphorylation. 1. Redox of NADH+H+ at Complex I - electrons to Complex I. Four protons pumped from matrix to inter-membrane space. 2. Redox of FADH2 at Complex II. Coenzyme Q moves electron to Complex III. 3. Redox of Complex III. Four protons move from the matrix to inter-membrane space. Carrier C moves electron to Complex IV. 4. Redox of Complex IV. Two protons are pumped from matrix to inter-membrane space. H20 is formed. 5. ATP Synthase action. Protons pumped to the matrix, ATP is formed.

Question 193

Define pharmacokinetics

Answer 193

The movement of drugs in the body.

Question 194

Name the four stages pharmacokinetics

Answer 194

1. Absorption 2. Distribution 3. Metabolism 4. Excretion

Question 195

Describe the routes of drug administration.

Answer 195

A. Paternal routes: 1. Intramuscular injections. - must have blood to the muscle - avoids first pass metabolism - rapid onset - poor usage in shock. 2. . Subcutaneous injections. - slower onset - avoids first pass metabolism - poor use in shock 3. Intravenous injections. - rapid onset - avoid first pass metabolism - more specific, titration of drug dose. - use can be poor in severe shock. Enteral routes: 1. Oral 2. Rectal 3. Lingual - safe - non invasive - subject to first pass metabolism - delayed onset - patient compliance can be low Other routes: Pulmonary - inhaled, absorption is poor. Topical - onto the skin. Sublingual sprays. Buccal.

Question 196

Define the term bioavailability.

Answer 196

The fraction of administered drug that reaches circulation to have an active effect.

Question 197

Name four factors that affect the bioavailability of drugs.

Answer 197

1. Hepatic first pass 2. Molecular weight 3. Gastric health 4. Ingestion of other foods and drugs

Question 198

Define the term loading dose.

Answer 198

The amount of drug administered to achieve target concentration.

Question 199

Define the term half-life (pharmacology)

Answer 199

The time taken for the plasma concentration to decrease by half.

Question 200

Define the term clearance.

Answer 200

The theoretical volume of plasma cleared of the drug per unit of time.

Question 201

Define the term steady state.

Answer 201

Where the drug administered is equal to the amount of drug cleared.

Question 202

Define pharmacodynamics.

Answer 202

The biochemical and physiological mechanisms that underpin drug action.

Question 203

Describe targets for drugs.

Answer 203

Drugs target receptors. Usually proteins, receptors affect: 1. Regulation of metabolism 2. Enzymes 3. Transport of proteins 4. Structure of proteins.

Question 204

Define the term affinity.

Answer 204

A measure of the ability of a drug to bind a receptor.

Question 205

Define the term efficacy.

Answer 205

The ability of a bound drug to produce it’s intended effect.

Question 206

Define the term agonist.

Answer 206

A molecule that binds to a receptor, mimicking it’s biological ligand, producing the same/ similar effect. Can be full or partial.

Question 207

Define the term antagonist.

Answer 207

A molecule that binds to it’s receptor and inhibits a biological response. It can be competitive or non-competitive.

Question 208

Define the term ED50.

Answer 208

Effective dose. The dose at which 50% of the population tested exhibit the desired effect.

Question 209

Define the term TD50.

Answer 209

Toxic dose. The dose at which 50% of the population tested exhibit toxic effects.

Question 210

Define the term LD50.

Answer 210

Lethal dose. The dose at which 50% of the population tested exhibit lethal effects.

Question 211

Describe the basic anatomy of the kidneys.

Answer 211

With the ureters, form the upper urinary tract. 1. Retroperitoneal, found at T12-L3 (left kidney is higher). 2. Four layers of fascia and fat. - Pararenal Fat - Renal Fascia - Perirenal Fat - Renal Capsule (fibrous) Structure of the kidney. 1. Cortex - outer 2. Medulla - inner. - divided into renal pyramids by renal columns. - drains into the renal papilla. - papilla drains to the minor calyx. - merge to form the major calyx. - drain to the renal pelvis - drains to the ureter. Through the hilum, formed by the renal fissures. - enter the bladder at the ureteral opening. Peristaltic, wave like contractions fill the bladder. Hydrostatic pressure and gravity aid this.

Question 212

List the functions of the upper urinary tract.

Answer 212

Kidneys and ureter. 1. Produce and transport urine 2. Filtration of blood 3. Maintenance of blood volume and pressure. 4. Acid-base buffering.

Question 213

Describe the arterial supply of the kidneys.

Answer 213

Served by renal arteries, which are branches of the abdominal aorta. Branch into suprarenal arteries (but can also arise independently from the Abdominal Aorta). Nephrons attach at the arcuate or cortical vessels. Renal veins drain into the Inferior Vena Cava.

Question 214

Describe the histology of the ureters.

Answer 214

1. Mucosa - mucous membrane with transitional epithelium. Goblet cells secrete mucous. 2. Lamina propria - areolar connective tissue with Lymphatics and blood vessels. 3. Muscularis - inner and outer longitudinal layers. 4. Adventitia - superficial fascia. Vascular access, Lymphatics, nerves. Structure.

Question 215

What organs contribute to the lower urinary tract?

Answer 215

Urinary bladder and urethra.

Question 216

What are the functions of the bladder?

Answer 216

1. Storage of urine 2. Capacity of around 500mls of urine. 3. Expulsion of urine (detruser muscle and two sphincters)

Question 217

Describe the anatomy of the bladder.

Answer 217

Overview: 1. Hollow and distensible organ. 2. Found in the anterior pelvic cavity. 3. Urine enters via the ureters at the trigone. 4. Folded with riggae.

Question 218

Describe the histology of the bladder.

Answer 218

Four layers. Similar to the ureters. 1. Mucosa - mucous membrane. With transitional epithelium. Goblet cells secrete urine. 2. Lamina propria - Areolar tissue, vascular, lymphatics. 3. Muscularis - three layers - inner, middle (circular) and outer. Form the detrusor muscle. 4. Adventitia - superficial fascia. Vascular, lymphatics and nerves.

Question 219

Describe the urethra in males and females.

Answer 219

Males: 1. 18-20cm 2. Carries urine and semen. 3. Three portions. Prostatic (prostate), membranous (pelvic floor. external sphincter is here) and spongy (penile). Females: 1. 3-5cm 2. Bladder - external urethral orifice. 3. Only urine. Sphincters: Internal: Males: circular smooth muscle at the neck to prevent premature ejaculation. Females: formed by the neck of the bladder. External: The same in both. - skeletal muscle. Voluntary.

Question 220

Briefly describe the gonads and the differences between male and female.

Answer 220

Males: Urinary and reproductive exocrine duct share the urethra. Genitalia are external. Penis and scrotum. Prostate is internal. Two membranes; (tunica) vaginalis (visceral and parietal layers) and albuginea (lobules and seminiferous tubules). Sperm: Produced in seminiferous tubules, travel to epididymis. Leave via ductus deferens/ vas deferens- enters prostatic urethra. Female: Internal. Separate from urethra. Ovaries, no direct contact with the tract. Uterine tubules provide transport for eggs. Produce: oestrogen and progesterone.

Question 221

Watch an Armando video on the kidneys. | Describe the microscopic structure and physiology of their kidneys.

Answer 221

Now.

Question 222

Describe the prostate gland.

Answer 222

1. . Located inferior to the neck of the bladder and superior to the external urethral sphincter. 2. Secretes proteolytic factors that prevent coagulation of semen. Prostate Specific Antigen. 3. Four regions. - Peripheral zone, contributes 7080% of Prostatic Ca. - central zone, very invasive if Ca. - Transitional zone - BPH. - Anterior zone - connective tissue.

Question 223

What is Benign Prostatic Hyperplasia?

Answer 223

The benign growth of the transitional zone of the prostate, causing organ enlargement. High levels of DHT are thought to contribute.

Question 224

What are the signs and symptoms of BPH?

Answer 224

1. Difficulty peeing 2. Incomplete urination 3. Frequent urination 4. Stop-start-slow stream. 5. Urgency to pee

Question 225

Describe the production and maturation of sperm in males.

Answer 225

1. Immature sperm produced in the seminiferous tubules. Travel to rete testes via straight tubules. 2. Travel to epididymis via efferent ductules. Mature here. 3. Ejected via the ductus deferens - vas deferens - prostatic urethra.

Question 226

Watch an Armandoh video on nephrology. | Describe filtration of the kidneys

Answer 226

Just do it.

Question 227

Describe renal flow. There’s 13 steps.

Answer 227

1. Renal artery 2. Segmental artery 3. Interlobar artery 4. Arcuate artery 5. Interlobular artery 6. Afferent arteriolar 7. Glomerular capillaries 8. Efferent capillaries 9. Peritubular capillary. 10. Interlobular vein 11. Arcuate vein 12. Interlobar vein 13. Renal vein

Question 228

Describe normal bladder function.

Answer 228

Influence by Anti Diuretic Hormone. Max ADH: 1mL/min Min ADH: 20mL/min Micturition: Three phases. 1. Storage phase. - passive filling. - Stretch sensation is received by the Sacral Spine S2-24. - hypogastric nerve at T12-L2 causes relaxation of the detrusor muscle (BA-R) and constriction of the internal sphincter (AC-R). - Pudental nerve is stimulated - external sphincter constricts (N-R). - pressure builds up. 2. Voiding phase - desire to urinate around 300mLs. - stretch receptors detect filling. - micturition centre inhibit hypogastric nerve. - parasympathetic fibres cause contraction of the detrusor muscles. - desire reduces once voiding begins. 3. Reflex phase - parasympathetic nerve is innervated to keep bladder contraction until urine is voided.

Question 229

Define screening

Answer 229

Screening is a Public Health Service which tests a defined population for risk of a certain disease. It is not diagnostic.

Question 230

State 10 criteria of screening. | Past question asks for six

Answer 230

1. The condition must be important to the population and the individual. 2. There should be an accepted treatment for those diagnosed. 3. There should be facilities for diagnosis treatment. 4. There should be a recognisable early/ asymptomatic stage. 5. There should be a suitable test 6. Test should be acceptable to the target population 7. The disease pathology should be adequately understood. 8. There should be agreed policy of who to treat. 9. Cost to benefit ratio acceptable. 10. Should have follow up.

Question 231

Name three screening programmes and their target age range.

Answer 231

1. Cervical Cancer. - smear test - Women 25-65 - 25-49 every 3 years - 50-65 every 5 years. 2. Breast Cancer. - mammogram - women 50-70 - every 3 years. 3. Bowel Cancer - two samples from bowel movements. - men and women 50-74 - every two years. Additional - 1. Abdominal Aortic Aneurysm. - ultrasound - men over 65. 2. New born screening - new borns - physical - hearing - blood spot

Question 232

Describe thermoregulation.

Answer 232

The maintenance of core body temperature at 37c (+/- 0.5) Two thermoreceptors: 1. Hypothalamic - arterial flow through the brain. - also acts as the control centre. 2. Peripheral - the external environment. Involuntary responses (in heat) 1. Vasodilation 2. Sweat 3. Hairs relax Visa versa in cold - with shivers, adrenaline and increased metabolism. Voluntary behaviour: Heat - doth clothing - find shade - take on fluids Cold - don clothing - seek shelter - huddle - try not to die

Question 233

Describe the physiology of fever.

Answer 233

Elevation of core body temperature at the “thermostat” in the hypothalamic temperature control centre. 1. Response to infection. IL-1 is released. Pyrogenic. 2. Prostaglandins secreted in the brain. The thermostat is reset. 3. Heat increase is promoted. Vasoconstriction. 4. Adrenaline and thyroxine increase metabolism. 5. Shivers generate heat. 6. Erector pili contract. “Chill phase” - cold sensation on skin. 7. Pyrogens decrease, and the hypothalamus resets. Heat loss is then promoted. 8. Sweating and peripheral vasodilation. 9. Erector pili relax - crisis phase. 10. Antipyretics, such as paracetamol, inhibit COX enzymes in the CNS to prevent prostaglandin production. Analgesic.

Question 234

Describe the anatomy of the ear.

Answer 234

Three regions. Outer - pinna/ auricle. - sebeceous and ceramenious glands. - external auditory meatus Middle - tympanic membrane - auditory ossicles (malleus, Incas, stapes) Inner - vestibule - cochlea - round and oval windows. - semi-circular canals - vestibular nerve (balance) - auditory nerve (hearing)

Question 235

Describe the physiology of hearing

Answer 235

1. Sound (changes in air pressure). Travel down auricle and external auditory meatus. 2. Sound is received by the tympanic membrane. 3. Sound is transferred (back and forth) Malleus - Incas - stapes (amplified by x22) 4. These auditory ossicles concentrate movement . Stampeding-vestibular joint transfers sound through the oval window. 5. Oval window moves back and forth - fluid pressure waves in the peri lymph of the scala vestibuli. 6. Travels to the scala tympani (tympanic duct). 7. Travels to the round window - relieves pressure. 8. This pressure wave moves end of lucid in the scala media (cochlear duct) against the organ of corti via the basilar membrane. 9. Hairs of the organ of corti brush against the tectorial membrane, which stimulates stereocilia to stimulate CNVIII. Higher pitch - low pitch.

Question 236

Describe the RAA system

Answer 236

Aims is to raise blood pressure. Three mechanisms from the junta-medullary apparatus. 1. Baroreceptors (- BP in the kidneys in the afferent arterioles) 2. Sympathetic nerve stimulation (B1-AN) 3. Macula densa mechanism (DCT detects NaCl. Low? = Renin. Renin (an enzyme) converts angiotensinogen to angiotensin I. Travels to the lung, and is converted by Angiotensin Converting Enzyme (ACE) to Angiotensin II. Angiotension II works on the Pituitary Gland (ADH) and the Adrenal Gland (Aldosterone) to raise blood pressure. Auto regulated loop.

Question 237

Describe eye anatomy.

Answer 237

Three layers. 1. Fibrous layer(s) - cornea (central passage for light) - sclera (white of eye) 2. Vascular layer - Iris (colour) - Pupil (light into eye) - Lens (focuses light) - ciliary body (controls lens shape) - chloroid (dark pigment, limits reflection) 3. Retina - neural portion - pigmented part (rod cells and cone cells) Cavities: 1. Anterior - two. Anterior, posterior. Aqueous humour. 2. Posterior - behind iris. Virtuous humour. Optic nerve, CNII. Orbital stuff: Superior rectus - CNII Inferior rectus - CNII Lateral rectus - CNVI Medial rectus - CNII Superior oblique - CNIV Inferior oblique - CNII

Question 238

What cranial nerve is responsible for vision?

Answer 238

CNII - Optic.

Question 239

Name the eye muscles and then nerve that innervates each. There are six.

Answer 239

1. Superior rectus - CNII (Oculomotor) 2. Inferior rectus - CNII (Oculomotor) 3. Lateral rectus - CNVI (Abducens) 4. Medial rectus - CNII (Oculomotor) 5. Superior oblique - CNIV (Trochlear) 6. Inferior oblique - CNII (Oculomotor)

Question 240

Describe tear production and drainage.

Answer 240

1. Produced by the lacrimal glands. Superior and lateral to the orbit. 2. Secreted onto the eye and drains lateral to medial and superior to inferior. 3. Drains to the lacrimal sac via the nasolacrimal gland. Functions: Lubricates the eye and removes dirt// washes the eye.

Question 241

Name the bones of the orbit and the borders.

Answer 241

Apparently we should patch the borders. Bones: 1. Maxilla 2. Zygomatic 3. Frontal 4. Palatine 5. Ethmoid 6. Sphenoid 7. Lacrimal

Question 242

Name the three cavities and four sinuses found in the skull.

Answer 242

3 cavities: 1. Nasal cavity 2. Oral cavity 3. Orbit 4 Sinuses: 1. Frontal 2. Maxillary 3. Sphenoid 4. Ethmoid

Question 243

Describe the structure of the nose.

Answer 243

Structure: 1. External nares 2. Conchae (superior, middle, inferior) 3. Internal nares 4. Nasopharynx 5. Nasolacrimal glands. 6. Pseudostratified ciliated columnar epithelium, goblet cells. 7. Olfactory epithelium at the posterior wall. CNI (Olfactory) Functions in breathing: 1. Filters air 2. Warms and humidifies air.

Question 244

Describe the innervation of the tongue.

Answer 244

1. Anterior 2/3 - Lingual branch of the mandibular division of the trigeminal nerve (CNIII) - taste - CNIII and facial nerve - CNCVII. 2. Posterior 1/3 - glossopharangeal (CNIX) 3. Movement - hypoglossal - CNXII

Question 245

Name the cranial nerves and their function.

Answer 245

1. CNI Olfactory - Smell 2. CNII Optic - Sight 3. CNIII Oculomotor - Movement of the eye 4. CNIV Trochlear - Superior oblique 5. CNV Trigeminal - taste, hearing. 6. CNVI Abducens - Stapedius muscle 7. CNVII Facial - tears and taste. 8. CNVIII Vestibulocochlear - Hearing and balance 9. CNIX Glosspharyngeal - Posterior 1/3 of the tongue 10. CNX Vagus - Heart, bronchi and lungs 11. CNXI (Spinal) Accessory - Trapezius 12. CNXII Hypoglossal - Movement of the tongue.

Question 246

Define the term Bacteriocidal

Answer 246

An agent that kills bacteria - Penicillin

Question 247

Define the term Bacteriostatic

Answer 247

An agent that inhibits bacterial growth - Trimethoprim

Question 248

Give examples of antibiotics and their mechanism of action.

Answer 248

1. Cell Wall Synthesis - Glycoproteins (Vancomycin) - Beta-Lactams (Pennicillins) 2. Protein Synthesis - Macrolides (Azithromycin) - Tetracylins (Tetracycline) 3. DNA Synthesis - Quinolones (Ciprofloxacin) 4. Metabolism - (Trimethoprim)

Question 249

In the brain, what is the Frontal Lobe responsible for?

Answer 249

Movement, co-ordination. Executive function. Higher thinking (reasoning, planning). Memory.

Question 250

In the brain, what is the Parietal Lobe responsible for?

Answer 250

Sensation and sensory information.

Question 251

In the brain, what is the Occipital Lobe responsible for?

Answer 251

Interpretation of visual data.

Question 252

In the brain, what is the Temporal Lobe responsible for?

Answer 252

Hearing

Question 253

In the brain, what is the Broca Area responsible for?

Answer 253

Speech. Frontal Lobe - clinically, if this is damaged, the patient can understand conversation but not speak.

Question 254

In the brain, what is the Wernicke Area responsible for?

Answer 254

Language and reading. Parietal/ temporal lobe. - clinically, if this is damage, the patient is able to speak however the words will amount to nonsense.

Question 255

What are the deep structures of the brain?

Answer 255

Four main structures. 1. The Limbic System - emotion, behaviour, learning and memory (via the hippocampus) 2. Basal Ganglia - control of movement and reward centre. 3. Hypothalamus - homeostasis 4. Thalamus - relays sensory information between the spinal cord and cerebral cortex.

Question 256

What are the layers of the meninges (superficial - deep).

Answer 256

1. Dura Mater 2. Arachnoid Mater 3. Pia Mater - this is where the CSF is found.

Question 257

What are the functions of CSF?

Answer 257

1. Nutritional support 2. Clearance of metabolites 3. Maintains intracranial pressure/ brain density 4. Bouyancy 5. Protect: shock transmission 6. Prevent: ischaemia 7. Homeostasis

Question 258

What are the three basic mechanisms by which bacteria are awarded resistance to antibiotics?

Answer 258

1. Mutation of the target 2. Expression of inactivating enzymes 3. Reduced access. (Expression of efflux pumps, lack of transport channels) - an example is B-Lactams resistance is conferred by altered porins (reduced uptake) - expression of B-Lactamases. (Can be countered by anti-enzymes like Tazocin)

Question 259

What are the three methods of antibiotic usage?

Answer 259

Guided: ideal, specific. Investigation dependant. Prophylactic: prevention. Targeted at high-risk groups. Empiric: based on clinical judgement. The best guess, with broad spectrum abx.

Question 260

What are the four allergic reaction types to antibiotics?

Answer 260

Type I - Anaphylaxis Type II - Haemolytic Anaemiaa Type III - Vasculitis Type IV - Delayed - non allergic reactions exist. D&V, seizures, bone marrow dysfunction.

Question 261

What are the three germ layers Post gastrulation? What example tissues arise from each?

Answer 261

1. Ectoderm - the skin, epithelial layers of the mouth and anus.. 2. Mesoderm - skeletal system, muscular system, dermis. 3. Endoderm - epithelial layers of the intestinal tract, liver, thymus.

Question 262

What does PICO stand for?

Answer 262

P: Population, problem or patient. I: Intervention C: Comparator, control O: Outcome

Question 263

What is Binge Eating Disorder?

Answer 263

Frequent or recurrent episodes of binge eating with compensatory behaviour. - eating very quickly - eating until uncomfortable full - eating lots when not hungry - eating alone due to embarrassment - feeling extreme guilt after eating

Question 264

What is Anorexia Nervosa?

Answer 264

A significant deficit in weight for the patients age, height and developmental stage, with persistent patterns that block restoration of normal body weight. Clinical criteria: BMI <18.5. Under 5th percentile in adults and children.

Question 265

What is Bulimia Nervosa?

Answer 265

Recurrent episodes of overeating, accompanied with inappropriate compensatory behaviour. Patients may make an effort to block wright gain. S/S - eroded teeth, Russell’s sign (purging, scratches on the back of the hand). May be within normal BMI, which separates it from Anorexia Nervosa. Can lead to G.I complications, cardiac arrhythmia and kidney damage.