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Flashcards in Phase 1 - Week 3 (Blood) Deck (123):

What are the functions of blood?

- Carries oxygen from lungs to tissue
- Carries carbon dioxide from tissues to lungs
- Clotting
- Healing
- Contains cells which fight infection


Describe the components of blood in terms of percentages.

43-48% - Cells
52-57% - Plasma


List the cells found in blood.

- Red blood cells (erythrocytes)
- White blood cells (leukocytes)
- Platelets (thrombocytes)



- Fluid component of blood
- Contains salts and organic compounds (including amino acids, lipids, vitamins, proteins and hormones)


What is the main protein found in plasma and what is its function?

Albumin - controls osmotic pressure



Number of RBC in blood (normal = 40%)


Describe the structure of erythrocytes

- Non-nucleated, biconcave-shaped cells
- Lack organelles - only have a plasma membrane, cytoskeleton, haemoglobin and glycolytic enzymes


Describe the life-cycle of erythrocytes

- RBCs circulate for 120 days
- Senescent RBCs are removed by phagocytosis or destroyed by haemolysis in the spleen
- RBCs are replaced in the circulation by reticulocytes which complete haemoglobin synthesis and maturation 1-2 days after entering the circulation
- Reticulocytes are produced by haemopoietic tissue in red bone marrow
- Before release from bone marrow RBCs shed their nuclei


Describe the function of erythrocytes

Transport of respiratory gases - oxygen/carbon dioxide. Oxygen goes from lungs to tissues and is then exchanged for carbon dioxide.


Explain how the structure of erythrocytes makes them suited to their function

- No nucleus means reduced weight and space for haemoglobin
- Biconcave disc for flexibility
- Membrane structure gives ability to withstand stress of turbulent circulation


Describe the structure of a RBC's membrane

Made of collapsible lattice of specialised proteins (cytoskeleton) and outer lipid bilayer. Lipid bilayer provides hydrophobic skin, consists mainly of a mixture of phospholipids and cholesterol.


Explain the structure and role of the cytoskeleton in RBCs

Responsible for maintaining shape, proteins include spectrin, actin, Ankyrin. Spectrin is most abundant consists of Alpha and Beta chains wound around each other.


Describe the structure of a Haemoglobin molecule

2 x Alpha chains
2 x Beta Chains
4 x Haem molecules with 4 Iron atoms


Describe the mechanism of action of Haemoglobin

Iron combines reversibly with oxygen. The individual globin chains interact to facilitate the offloading of oxygen at lower oxygen saturations. Haemoglobin has a high affinity for oxygen in the lungs and a low affinity for oxygen in the tissues.


Describe the production of platelets

Platelets are small cytoplasmic discoid fragments derived from megakaryocytes under the control of thrompoietin, a glycoprotein produced in the kidneys and liver. Magekaryocytes develop cytoplasmic projections that become proplatelets which fragment into platelets (takes 7-10 days). Platelets bind and degrade thrombopoietin, a mechanism that regulates platelet production.


Describe the structure of the plasma membrane of platelets.

Coated by glycoprotein 1b and GP2b-GP3a, involved in the attachment of platelets of platelets to Von Willebrand's factor. Membrane is invaginated to form a system of cytoplasmic channels called the invaginated membrane system.


What is the role of Von Willebrand's factor in platelet function

Adhesion of platelets to the vascular endothelium is mediated by VWF that also carries factor VIII coagulation factor.


Role of the invaginated system in platelets

Allows for the absorption of clotting factors and the release of secretory products stored in granules in thrombin-activated platelets


Describe the structure of the central region of platelets

Granulomere - contains mitochondria, rough endoplasmic reticulum (RER), the Golgi apparatus and 3 distinct types of granules


List the granules found in platelets

1. Alpha granules
2. Dense core granules
3. Lysosomal granules


Alpha granules

Store proteins involved in Haemostatic functions, including platelet adhesion (fibrinogen, thrombospondin, vitronutin, laminin and VWF), blood coagulation (plasminogen), growth factors for endothelial cell repair and microbial proteins


Dense core granules

Containing mediators of vascular tone (serotonin, ADP, phosphate)


Lysosomal granules

Containing hydrolytic enzymes participating in the dissolution of thrombi


Describe the structure of the periphery of platelets

Hyalomere - contains microtubules and microfilaments that regulate platelet shape change, motility towards the site of injury and infection and release of granule contents.


Stages of Haemostasis

1. Vasoconstriction
2. Platelet aggregation (formation of primary platelet plug)
3. Blood coagulation (formation of definitive fibrin clot)


Explain the events of the vasoconstriction phase of haemostasis

- Immediate vasoconstriction of injured vessel and reflex constriction of adjacent small arteries/aterioles
responsible for initial slowing of blood flow in injured area to prevent blood loss
- Reduced blood flow allows contact activation of platelets and coagulation
- Vasoactive amines TXA2 (thromboxane A2) serotonin etc. liberated from adherent platelets releasing their granule contents during platelet aggregation have vasoconstrictive activity
- Involves contraction of smooth muscle cells in BVs
- Becomes more effective as damage increases, more effective in small BVs


How is spontaneous clotting of blood prevented in blood vessels?

- Structure of the endothelial lining - smooth vessel walls.
- Chemicals to prevent clotting - thrombomodulin, nitric oxide, prostacyclin


Describe the process of primary platelet plug formation

1. Break in endothelial lining
2. Initial adherance of platelets (via glycoprotein receptors - GP1A/GP1B - on platelet surface which interact with the extracellular matrix) to exposed connective tissue mediated by VWF
3. Collagen exposure and thrombin generated through activation of Tissue Factor produced at the site of injury cause the adherent platelets to release their granule contents and activate platelet prostaglandin synthesis leading to the formation of TXA2 (causes further vasoconstriction)
4. Released ADP from granules causes platelets to swell and aggregate
5. Platelets roll over exposed VWF in direction of blood flow and GP11a/GP111b receptors become activated, resulting in firmer binding of platelets. Additional platelets from circulating blood are drawn to the area of injury.
6. Continuing platelet aggregation promotes the growth of the Haemostatic plug, which soon covers the exposed connective tissue


Describe the function of the primary platelet plug

The unstable primary haemostatic plug produced by these platelet reactions in the first minute or so following injury is usually sufficient to provide temporary control of bleeding.


When is definitive Haemostasis achieved?

When Fibrin formed by blood coagulation is added to the platelet mass and platelet- induced clot retraction/compaction occurs.


Briefly explain the steps involved in the clotting cascade.

1. Initiation (Extrinsic Pathway)
2. Amplification (Intrinsic Pathway)
3. Common pathway


How is blood coagulation initiated?

After vascular injury, when the membrane-bound Tissue factor is exposed and activated.


Describe the steps involved in the Extrinsic Pathway of blood coagulation

1. Tissue factor + plasma factor VII = Factor VIIa-Tissue factor (Extrinsic Factor Xase)
2. Factor IX = Factor IXa and Factor X = Factor Xa by Extrinsic Factor Xase
3. Factor IXa and Factor Xa convert Prothrombin = Thrombin


Why must coagulation be amplified after the Extrinsic Pathway

Not enough thrombin is produced during extrinsic pathway to initiate fibrin polymerisation.


Describe the steps involved in the Intrinsic Pathway of blood coagulation

1. Factor VII and Factor V = Factor VIIa and Factor Va by the small amounts of thrombin generated during initiation
2. XII = XIIIa due to exposed collagen
XI = XIa due to XIIa
IX = IXa due to XIa (and calcium)
3. Factor IXa and Factor VIIa = Intrinsic Xase


Describe the steps involved in the Common Pathway of blood coagulation

1. Extrinsic + Intrinsic Xase activate Factor X = Factor Xa
2. Factor Xa + Va + PL (phospholipid) + calcium = Prothrombinase complex
3. Promthrombinase activates Prothrombin = Thrombin
4. Thrombin converts Fibrinogen = Cross linked Fibrin
Thrombin activates Factor XIII = Factor XIIIa which also contributes to the Fibrinogen = Fibrin reaction


Explain how Thrombin converts Fibrinogen to cross-linked Fibrin.

Thrombin hydrolyses Fibrinogen releasing Fibrinopeptides A and B to form Fibrin monomers. Fibrin monomers link spontaneously by hydrogen bonds to form a loose insoluble fibrin polymer. Factor XII is also activated by thrombin and stabilises the Fibrin polymers with the formation of covalent bond cross-links.


What is the role of Vitamin K in blood coagulation?

The activity of factors II, VII, IX and X is dependent on Vitamin K which is responsible for carboxylation of a number of terminal glutamic acid residues on the molecules.


Describe the transition from platelet to fibrin of the Haemostatic plug

The fibrin component of the Haemostatic plug increases as the fused platelets completely degranulate and autolyse and after a few hours the entire Haemostatic plug is transformed into a solid mass of cross-linked fibrin.



The process that prevents clots from growing and becoming problematic


Describe the process of fibrinolysis

Plasminogen = Plasmin by activators either from the vessel wall (Intrinsic activation) or from the tissues - extrinsic activation


How does Plasmin prevent growth of thrombi at the site of injury?

Plasmin is capable of digesting fibrinogen, fibrin, factors V and VIII etc.


Where are the cellular components of blood produced?

In bone marrow by Haematopoietic stem cells


List the populations of cells found in bone barrow

1. Haematopoietic stem cells capable of self-renewal
2. Committed precursor cells responsible for the generation of distinct cell lineages
3. Maturing cells, resulting from the differentiation of the committed precursor cell population


List the divisions in lineage which can result from Haematopoietic Stem Cells

1. Lymphoid stem cells - mature into T cell precursors and B cell precursors

2. Myeloid Stem Cells - mature into Granulocyte CFUs, Eosinophil CFUs, Basophil CFUs, Megakaryocyte CFUs and Erythroid CFUs


List the cell types that T cell precursors can mature into

- Natural Killer Cells
- T cells - Cytotoxic or Helper


List the cell types that B cell precursors can mature into

B cells


List the cell types that granulocyte CFUs can mature into

- Neutrophils
- Monocytes (which mature into Macrophages)


Describe the cell types that can be produced from:
a) Eosinophil CFUs
b) Basophil CFUs
c) Megakaryocyte CFUs
d) Erythroid CFUs

a) Eosinophils
b) Basophils
c) Megakaryocytes which mature into platelets
d) Red Blood cells (Erythrocytes)


List the major groups of Haematopoietic Growth Factors

1. Colony stimulating factors
2. Erythropoietin and Thrombopoietin
3. Cytokines



Production of new Erythrocytes, constant process as old RBCs are replaced


Describe the process of Erythropoiesis

Erythroid CFU --> Proerythroblasts --> Basophilic erythroblast --> Polychromatophilic erythroblast --> Orthochromatic erythroblasts --> Reticulocyte --> Erythrocyte


How is RBC replacement stimulated after blood loss?

1. Peritubular cells in the kidneys recognise that the oxygen level in the blood has decreased (due to loss of RBC) and secrete the hormone Erythropoietin.
2. Erythropoietin travels in the bloodstream to bone marrow which stimulates an increase in the activity of HSCs to produce more cells required to replace lost cells


Describe how the components of blood other than RBCs are replaced after blood loss

Plasma is mostly water, so water retention by kidneys helps make up lost plasma. Salts in plasma are absorbed through the digestive system. All blood proteins are synthesised in the liver.


Describe the effects of blood loss on the body

- All components of blood are lost equally
- Oxygen carry capacity of blood drops - causes shock
- Clotting ability drops


Explain the cause of Shock

After blood loss, the drop in oxygen carrying capacity due to the decrease in RBCs means that oxygenation of tissues is not adequate to maintain normal metabolic functions


List the types of Shock

1. Hypovolaemic
- Haemorrhagic (external/internal)
- loss of blood from intravascular space

2. Cardiogenic
- Pump failure

3. Septic
- Fluid redistribution - leaking capillaries, vasodilation

4. Spinal/neuro
- Altered/loss of vascular tone

5. Anaphlylactic
- Combination (fluid leaking/cardiac failure etc.)


Describe the symptoms associated with shock

- Increase in pulse
- Decrease in blood pressure - last sign
- Increase in respiratory rate (v. reliable measure)
- Decrease in urine output
- Altered mental status


Describe the classifications of Hypovolaemic Shock in terms of blood loss (ml)

Class I = up to 750
Class II = 750-1500
Class III = 1500-2000
Class IV = >2000


Describe the classifications of Hypovolaemic Shock in terms of total % blood loss

Class I = up to 15%
Class II = 15-30%
Class III = 30-40%
Class IV = >40%


Describe the classificatios of Hypovolaemic Shock in terms of pulse rate

Class I = <100
Class II = >100
Class III = >120
Class IV = >140


Describe the classifications of Hypovolaemic Shock in terms of blood pressure

Class I = Normal
Class II = Normal
Class III = Decreased
Class IV = Decreased


Describe the classifications of Hypovolaemic Shock in terms of respiration rate

Class I = 14-20
Class II = 20-30
Class III = 30-40
Class IV = >40


Describe the classifications of Hypovolaemic Shock in terms of urine output

Class I = >30 mls/hr
Class II = 20-30 mls/hr
Class III = 5-15 mls/hr
Class IV = negligible


Describe the classifications of Hypovolaemic Shock in terms of mental status

Class I = Normal
Class II = Mild anxiety
Class III = Anxious
Class IV = Confused


List some examples of wounds

1. Abrasions
2. Degloving
3. Incision
4. Laceration
5. Bites
6. Burns


Describe treatment of abrasions

- Clean debris (may be moved to theatre to scrub)
- Bleeding is not usually an issue


Describe degloving wounds

- Skin/blood supply torn off
- Major trauma
- Commonly limbs/digits


Describe incisions + treatment

- Sharp/penetrating
- Stab (deep not wide)/slash
- Look less dramatic but v. deep
- Must investigate for underlying damage
- Can loss blood into chest, abdomen, pelvis, long bones


Describe lacerations + treatment

- Due to blunt force trauma only
- Skin splitting, tissue bridging, irregular depths/edges
- Irrigate/clean
- Close - glue/steristrips/staples/stitches


Describe bites + treatment

- Small entry wound
- Possibly deep
- Foreign body contamination
- Animal
-Human - Human blood borne viruses
- Antibiotics, tetanus, vaccines
- Irrigation, delayed closure?(infection)


Describe the stages of ATLS

Advanced Trauma Life Support:
A - Airway with cervical spine control (risk of broken neck)
B - Breathing with oxygenation
C - Circulation with haemorrhage control
D - Disability (neurological)
E - Exposure (prevent cold/expose more injuries)


Explain the observations made in the Airway stage of ATLS

- Check for foreign body, swelling fractures
- Check OPA - oral/pharyngeal airway and NPA - nasal/pharyngeal airway


Explain the observations made in the Breathing stage of ATLS

- Check for fractures (sternum/scapula)
- Can have 'flail' - loose part of ribs due to fracture, falls in when inhaling
- Haemothorax - collection of blood in pleural space
- Pneumothorax - collection of air in pleural space (collapsed lung)


Explain the observations made in the Circulation stage of ATLS

- Check for cardiac tamponade - bleeding between surface of heart and pericardium limiting movement of heart
- Tension pneumothorax
- Major haemothorax - >1l blood in chest


Describe the role of the triage nurse

- First point of contact for patients in emergency setting
- Assess patients - type of injury or illness, its severity, symptoms, patient explanation of emergency, and vital signs - and decide who will be seen first (traffic light system)


Describe the first aid response to wounds which may contain foreign objects

- Ensure airway is clear (if bleeding from mouth/nose)
- Wear gloves to protect from infection
- Remove clothing around wound
- Don't pull foreign objects out of wound - could be acting as a plug to reduce bleeding
- Apply pressure on either side of the object
- Lie patient down/raise legs to treat for shock (unless legs are injured)
- Apply bandage - check circulation


Describe the major planes used in anatomy

1. Transverse = divides body into superior and inferior structures
2. Sagittal = divides body into left and right structures
3. Coronal = divides body into anterior and posterior structures



Front/closer to the front



Back/closer to the back



Above another part of the body



Below another part of the body



Closer to the centre of the body



Further from the centre of the body



Closer to the surface of the body



Further from the surface of the body



Closer to the midline of the body



Further from the midline of the body



Structures derived from the front of the embryo



Structures derived from the back of the embryo



Structures close to the top of the body



Structures close to the bottom of the body


List the regions of the abdomen

1. Right hypochondrium (top right)
2. Epigastric (top middle)
3. Left hypochondrium (top left)
4. Right lumbar (middle right)
5. Umbilical (middle)
6. Left lumbar (middle left)
7. Right iliac (bottom right)
8. Hypogastric (bottom middle)
9. Left iliac (bottom left)



Movement that decreases the angle between body parts



Movement that increases the angle between body parts



Motion that pulls structure away from the midline of the body or limb



Motion that pulls structure closer to the midline of the body or limb



Movement in a superior direction



Movement in an inferior direction



Rotation of the forearm/foot so that the palm or sole is facing posteriorly



Rotation of the forearm/foot so that the palm or sole is facing anteriorly



Movements that tilt the sole of the foot away from the midline of the body



Movements that tilt the sole of the foot away from the midline of the body



Can give rise to embryonic membrane - any type of cell in the adult human body



Can give rise to any type of cell in the adult human body



Can give rise to tissue specific cell type of the human body



Can give rise to one specific adult body tissue cell


Compare adult (tissue) and embryonic stem cells

Adult (tissue)
-Multipotent or single type
- Able to become specialised cell types within residing tissue or specific cell type of the tissue
- Useful for transplant
- Difficult to culture + expand
- Less controversial ethically

- Pluripotent
- Able to become any cell type in body
- Rejection problem
- Easier to culture + expand
- Extremely controversial - any embryo has potential to grow into baby


Define differentiation

The process by which relatively unspecialised cells, e.g. stem cells, acquire specialised structural and/or functional features that characterise the cells, tissue or organs of the organism


Define Standard Infection Control Precautions (SICP)

Used by all staff, in all care settings, at all times, for all pateints/persons whether infection is known to be present or not to ensure the safety of those being cared for, staff and visitors in the care environment


List the sources of potential infection

1. Blood and other body fluids
2. Secretions or excretions (excluding sweat)
3. Non-intact skin
4. Mucous membranes
5. Equipment or items in care environment that could be contiminated


Describe the standard precautions involved in SICP

- Hand hygiene at the 5 moments
- Care in use and disposal of sharps
- Correct use of personal protective equipment for contact with all blood, body fluids, secretions + excretions
- Providing care in a suitably clean environment with adequate decontaminated equipment
- Safe disposal of waste
- Safe management of use linen


Outline the 5 moments of hand hygiene

1. Before touching patient
2. Before clean/aseptic procedures
3. After touching a patient
4 After touching a patient's immediate surroundings
5. After body fluid exposure


List the types of Personal Protective Equipment (PPE)

1. Non-latex disposable gloves
2. Disposable aprons
3. Sterile gloves
4. Sterile aprons
5. Eye protection
6. Masks and respirators



All genes an organisms an organism posesses



All the mRNA molecules expressed from the genome



All the proteins that can be expressed by an organism


How are proteins encoded?

Read from mRNA in codons of 3 bases according to the genetic code


How many amino acids are there?



How can more than one protein be produced from one gene?

Post-translational modifications


List the possible types of post-translational modifications

1. Glycosylation (sugar chains added)
2. Phosphorylation
3. Other - hydroxylation, Prenylation, Acyl lipidation etc.


Role of the Smooth ER

Lipid synthesis + metabolism


Role of the Rough ER

Protein secretion