S4 L1 Control of Body Fluid Volume and Osmolality Flashcards
What 2 ‘main’ systems occur when decreased blood pressure?
What 2 ‘main’ systems occur when increased blood pressure?
What is the RAAS system?
What is renin?
Where is renin stored?
What leads to renin release?
3 ways that cause renin release?
Decreased blood pressure, leading to increasing of blood pressure:
Equation showing the RAAS system
Roles of angiotensin II
Descreased blood pressure leading to increasing of blood pressure:
Prostagladins:
- Which part of the kidneys are these secreted from?
- Results in…
Increased Blood Pressure:
- ANP: Which cells produce this? What does ANP do (where does it act)?
Increased blood pressure leading to decrease of blood pressure:
Starlings forces affecting blood pressure?
What are peritubular capillaries? Which part of the kidney?
Increased blood pressure leading to decreasing blood pressure:
Renal artery blood pressure, how does this affect/lead to changes in blood pressure?
Specific terms associated with increased sodium excretion, increased water excretion?
Congestive cardiac failure:
- Occurs when…
- Leads to (affect on the kidney)…
- How is this sensed by the kidney?
- How does the kidney respond?
- What symptoms does this lead to?
- Management?
Hypervolaemia
- What is this?
- Why does it happen? (causes)
- Which comparment is increased?
- Symptoms and explain them
Hypovolemia and shock
- What is shock?
- Problems with shock for organs?
- Specific problems with the kidney?
- How can the body respond to shock, to try and stop it (specific mechanisms)
Body’s response to shock:
A severe decrease in circulating volume stimulates sympathetic activity to
maintain the BP by:
• Tachycardia
• Peripheral vasoconstriction
• Increase in myocardial contractility to try and increase flow around the body
Hypovolemic shock cont:
- Occur when…
- What protective mechanism occurs in the kidneys to stop problems associated with vasoconstriction?
- 2 major consequences of losing large amounts of fluid
- Treatment
Treatment:
• Treatment of hypovolemic shock requires fluid replacement to restore extracellular volume.
• If blood flow to the kidneys is not restored, acute kidney injury results from tissue anoxia and necrosis
Hypertensive renal disease
- How does the body try to stop this from happening (mechanism)
- Hypertensive changes seen in the kidney… (2)
- Which diseases in the kidney can result in hypertension?
- Example of one
Osmolality:
- Regulation of osmolality:
What is osmolality? What is sensed? Sensors by? Efferent pathways (2)? Effectors of these pathways? What is affected?
Osmoreceptors (sense change)
- General location? also, more specific location?
- Senses?
- Which responses occur?
ADH:
- Type of hormone?
- Synthesised in which nucleus and where in the brain?
- Secreted from?
- What triggers ADH release?
- Affect on aquaporins? What does this then mean?
ADH is a peptide hormone synthesized in the supraoptic nucleus of the hypothalamus as a large precursor molecule. It is transported to the posterior pituitary gland, where its synthesis is completed and it is stored until release.
↑in plasma osmolality triggers ADH release. Leading to:
• Reduced water excretion (V2 receptormediated)
-> ADH binds to V2 receptors on the basal membrane.
- G-protein-coupled receptors, when activated, cause fusion of inactive aquaporin 2 vesicles with the luminal membrane.
- Creates a channel through with water can pass
- Passive flow of water
• Blood vessel vasoconstriction (V1 receptor-mediated)
Efferent pathway - ADH
- how does ADH affect water excretion (specific name)
- Feedback type
Osmotic V Haemodynamic
- Changes in BP have an effect on the response to changes in osmolarity?
- If low BP, start releasing ADH at _______ osmolality? If high BP, start releasing ADH at _______ osmolality?
Efferent pathway: Thirst
- Why needed?
- Thirst is stimulated by…
Large deficits in water (or increase in salt) only partially compensated for in the kidney • Ingestion is the ultimate compensation
Stimulated by an increase in plasma osmolarity (also by reduced ECF
volume) • Thirst increases intake of free water
