EXAM 1: Lecture 7 Flashcards
What is the role of the thyroid in the body?
The thyroid plays a crucial role in regulating metabolic demand and cardiac function.
What is hyperthyroidism?
A condition characterized by an increase in heart rate at rest due to excess thyroid hormone.
What are the two primary thyroid hormones?
- T3 (triiodothyronine)
- T4 (thyroxine)
What percentage of thyroid hormone released is T4?
93%
What is a goiter?
A protrusion of the neck caused by an enlarged thyroid gland.
What controls the release of thyroid hormones?
Thyroid stimulating hormone (TSH) from the anterior pituitary gland.
What does TRH stand for?
Thyrotropin releasing hormone.
True or False: T3 and T4 are lipid soluble compounds.
True.
What is the main source of iodide in our diet?
Iodide is typically added to table salt.
What is the function of iodinease?
An enzyme that converts T4 to T3 by removing one iodide.
What happens to the body when thyroid hormone is deficient during growth?
Major deficiencies in the central nervous system, leading to personality, cognition, or memory issues.
What is the feedback mechanism involving TSH and TRH?
When TSH increases, it stimulates more thyroid hormones, while excess thyroid hormones reduce TRH production.
What are the three main protein carriers for thyroid hormones?
- Thyroxine binding globulin (TBG)
- Thyroxine binding pre-albumin
- Albumin
What is the predominant form of thyroid hormone that binds to receptors?
T3 is the active form that binds to thyroid hormone receptors.
What is a thyroid storm?
A condition where thyroid hormone acts rapidly, unlike the usual long-term effects.
What are the consequences of severing both recurrent laryngeal nerves during surgery?
Loss of the ability to speak.
What are common signs of Graves’ disease?
- Exophthalmos (protruding eyes)
- Goiter
Fill in the blank: The thyroid hormone primarily increases ________ in the body.
metabolic rate
What is the anterior pituitary gland also known as?
Adenohypophysis.
In the context of thyroid hormone, what does T1 and T2 refer to?
- T1: Monoiodotyrosine
- T2: Diiodotyrosine
What is the role of the hypothalamus in thyroid hormone regulation?
It monitors body conditions and adjusts TRH release to control TSH and thyroid hormone levels.
True or False: The thyroid hormone can directly cross the nuclear envelope.
True.
What is exophthalmos a result of?
Excessive thyroid hormone in hyperthyroidism
Exophthalmos is not seen in hypothyroidism.
What condition is characterized by a large goiter and exophthalmos?
Hyperthyroidism
Specifically, this is often associated with Graves’ disease.
How does hyperthyroidism affect cholesterol levels?
It causes a reduction in blood cholesterol levels
Cholesterol is consumed at the cellular level faster than normal.
What autoimmune disease causes hyperthyroidism?
Graves’ disease
It involves the production of antibodies that activate TSH receptors.
What is the effect of antibodies in Graves’ disease?
They increase activity at the thyroid gland
This results in excessive thyroid hormone production.
What is Hashimoto’s thyroiditis?
A disease that produces antibodies that destroy the thyroid gland
It can lead to complete destruction of the thyroid if untreated.
What is the role of iodide in thyroid hormone production?
Iodide is necessary to form T3 and T4
It attaches to tyrosine to create these hormones.
What happens when there is an iodide deficiency?
It leads to increased TSH and an enlarged thyroid gland/goiter
This results in hypothyroidism due to lack of hormone production.
What is a treatment for iodide deficiency?
Adding iodide to the diet
Commonly done through iodized salt.
What is the preferred treatment for thyroid cancer?
Radioactive iodide (I-131)
It targets tumors specifically in the thyroid gland.
What happens with excess iodide consumption?
It interferes with thyroid hormone production
Massive amounts can confuse the cellular system.
True or False: High iodide intake can be used to treat acute hyperthyroidism.
True
It temporarily shuts down the thyroid gland.
What is the main concern with severe hypothyroidism?
Developmental problems and increased risk of atherosclerosis
High cholesterol levels lead to thicker blood vessel walls.
Why are T3 and T4 difficult to measure in plasma?
They are lipid soluble
This complicates the detection of hypo and hyperthyroidism.
What is the synthetic version of thyroid hormone used for treatment?
Synthroid
Patient compliance for this medication is often low.
What is cardiogenic shock?
A problem with the heart’s ability to pump effectively
Often seen in heart attack patients.
What can cause venous return pathologies leading to cardiogenic shock?
Hemorrhage or embolism
Both affect blood flow back to the heart.
What induces neurogenic shock?
Volatile anesthetics and high spinal procedures
They reduce CNS function affecting cardiovascular stability.
What triggers anaphylactic shock?
Severe immune system reactions to allergens
Common triggers include latex and peanuts.
What is septic shock caused by?
Generalized and blood-borne infections
Typically associated with gram-positive bacteria.
What is hypovolemic shock?
The most common form of shock, caused by blood loss or low fluid intake
Can occur with as little as 8 ounces of fluid per day.
What happens to arterial pressure and cardiac output with 10% blood loss?
Both remain relatively normal
The body compensates effectively.
What is the consequence of losing more than 20% of blood volume?
Decreased chance of survival
Cardiac output and blood pressure become critical.
What characterizes non-progressive shock?
The body compensates for blood loss without major organ failure
Blood pressure remains above 50% of normal.
What happens during progressive shock?
Blood pressure drops below 45% of normal leading to organ failure
Survival chances decrease significantly.
What happens to blood pressure in progressive shock?
Blood pressure drops down to less than 45% of normal
This leads to reduced blood volume available to assist the cardiovascular system.
What is the primary cause of falling into shock?
Issues related to the circulatory system
What is necessary for delivering nutrients to tissues?
A certain cardiac output
What happens in anaphylactic shock?
There is a lack of tone in the circulatory system
What impact does sepsis have on the body?
It disrupts normal sympathetic nervous system activity
What is a common approach to dealing with shock?
Replacing what is missing
What occurs when the heart is damaged?
Filling pressures will increase
What compensatory mechanism does the nervous system use to help a failing heart?
It tightens the blood vessels to increase filling pressure
What is the minimum cardiac output required for a healthy person?
5 liters of blood per minute
What happens if cardiac output cannot reach 5L/min?
The patient may worsen and not survive
What medications can support cardiac output?
- Cardiac glycoside
- Milrinone (phosphodiesterase inhibitor)
- Digoxin
What is the role of medications in heart failure management?
They provide support to reach critical cardiac output levels
What do kidneys do in response to low blood pressure in heart failure?
They retain fluid and electrolytes
What happens if the kidneys retain too much fluid in heart failure?
It can worsen the condition
What is the significance of point C in venous return profiles?
Kidney’s help is useful in achieving 5L/min of cardiac output
What occurs from points D-E in the venous return profile?
Significant decline in cardiac output due to excessive fluid retention
What is a potential consequence of the heart walls stretching excessively?
It can lead to worsening heart function
What do diuretics do for chronic heart failure patients?
Prevent kidneys from excessive fluid retention
What blood pressure is optimal for heart failure patients?
100mmHg, but lower pressures can be functional
Is arterial blood pressure a substitute for measuring cardiac output?
No, it has limitations
