Physiology Of Shock Flashcards
What is the definition of shock?
Complex physiological syndrome
Life-threatening condition with variety of causes
Inadequate delivery of oxygen and nutritive substances to the tissues
Occurs when circulatory system fails to carry out essential functions eg blood flow impaired
What are the 3 components that need to be met for adequate blood flow?
1) effective pump
2) effective circulatory system
3) adequate blood flow
What causes shock to occur?
One of the three components contributing to supply of oxygen/nutrients to the cell in compromised
1) reduction in circulatory volume
2) failure of effective pump
3) lack of blood vessel tone/blood remaining in enlarged vascular component rather than returning to the heart
What is hypovolaemic shock and 3 possible causes?
Loss of intravascular volume
1) haemorrhage
2) loss of other body fluids
3) severe vomiting/diahorrea
What is cardiogenic shock and 3 possible causes?
‘Pump’ failure
1) myocardial infarction
2) HR/BP disturbances
3) medications
What is vascular shock and 3 possible causes?
Loss of vascular tone
1) septic shock
2) toxic shock
3) anaphylaxis (intense antigen-antibody reaction
What is neurogenic shock and 3 possible causes?
Loss of vascular tone due to lack of neurological control
1) severe emotional experience stimulates vagal slowly of the heart
2) spinal injury
3) head injury
How does TF maintain homeostasis of the internal environment?
Brings oxygen and nutrients to cells, while removing carbon dioxide and other waste products of metabolism
How does hypovolaemic shock reduce tissue perfusion?
Reduced blood flow- reduces perfusion of tissues- Fall in nutrients reaching tissue cells- accumulation of toxic waste products- may lead to death of cells
What are the 3 key aspects of control over blood pressure?
1) cardiac output
2) Peripheral resistance
3) blood volume
What is cardiac output?
Amount of blood pumped out of the heart during a minute
Stroke volume x HR
What is stoke volume?
Amount of blood pumped out of the left ventricle during each contraction
What is Peripheral resistance?
Force created by the friction between blood and walls of blood vessels
What is the main function of the RAAS?
Responds to changes in blood volume and pressure
When BP falls, renin-secreting cells in kidney are stimulated to secrete renin
What is the outcome of lack of oxygen available to cells?
Carbon dioxide build up so energy production falls
Anaerobic respiration takes place
Lack of energy- cell dysfunction and alteration in cell membrane permeability
