endocrine system

A comprehensive set of flashcards covering key concepts from Anatomy and Physiology Part 2, including homeostasis, feedback mechanisms, and hormone functions.

What is homeostasis?

The ability to maintain a relatively stable internal environment in an ever-changing world.

What happens to homeostatic mechanisms as we age?

They become less efficient, making us more susceptible to disease.

What percentage of homeostatic feedback loops are negative feedback systems?

99%.

List some examples of negative feedback systems in the body.

Body temperature, body pH, blood glucose levels, blood pressure, and calcium levels.

What is the function of insulin?

To lower blood glucose levels by facilitating its uptake by body cells.

What does glucagon do when blood glucose levels are low?

Stimulates the liver to break down glycogen and release glucose into the blood.

What is positive feedback?

A mechanism where the output enhances or increases the original stimulus.

Give an example of positive feedback in the human body.

Uterine contractions during childbirth stimulated by oxytocin.

What role do hormones play in the endocrine system?

They influence metabolic activities of cells.

What are hormones?

Chemical messengers secreted into the bloodstream that stimulate responses in other tissues or organs.

Name one major endocrine gland involved in hormone production.

Pituitary gland.

How do exocrine glands differ from endocrine glands?

Exocrine glands have ducts to carry secretions to a surface, while endocrine glands release hormones directly into the bloodstream.

What is the primary effect of the nervous system on endocrine glands?

It modifies their stimulation and negative feedback mechanisms.

What are amino acid-based hormones?

Hormones composed of amino acids that are water-soluble and cannot pass through cell membranes.

What distinguishes steroid hormones from amino acid-based hormones?

Steroid hormones are synthesized from cholesterol and are lipophilic, allowing them to pass through cell membranes.

How do first messenger hormones transmit signals?

By binding to receptors on the cell membrane to activate second messengers inside the cell.

What is ADH and its function?

Antidiuretic hormone helps prevent dehydration by increasing water reabsorption in kidneys.

What triggers the release of oxytocin?

It is released during childbirth and suckling of an infant.

What is the role of the hypothalamus in the endocrine system?

It regulates many endocrine glands and produces releasing and inhibiting hormones.

What is the function of the anterior pituitary gland?

It synthesizes and secretes six major hormones that regulate various body functions.

What does growth hormone (GH) stimulate in the body?

It stimulates tissue growth, protein synthesis, and overall metabolism.

What condition results from excess growth hormone secretion in children?

Gigantism.

What condition arises from excessive growth hormone in adults?

Acromegaly.

What does the thyroid gland primarily regulate?

Metabolism and energy production.

What are T3 and T4 hormones responsible for?

Regulating the body's metabolism and energy levels.

What is a goiter?

An enlarged thyroid gland, often due to iodine deficiency.

How does calcitonin affect calcium levels in the blood?

It lowers blood calcium levels by promoting calcium deposition in bones.

What is the role of parathyroid hormone (PTH)?

It raises blood calcium levels by stimulating osteoclast activity.

What are the adrenal glands responsible for?

Releasing hormones related to stress, salt, sugar, and sex.

What is the primary hormone released by the adrenal medulla?

Epinephrine (adrenaline).

What is Cushing's disease?

A condition due to hypersecretion of ACTH or cortisol, leading to various symptoms like high blood pressure and weight gain.

What does aldosterone regulate?

Sodium and potassium balance in the body.

How do glucocorticoids like cortisol affect the body?

They increase blood sugar levels and reduce inflammation.

What condition results from underproduction of adrenal hormones?

Addison's disease.

What can excessive cortisol lead to?

Muscle wasting and weight gain, known as Cushing's disease.

What effect does the sympathetic nervous system have on the body?

Increases heart rate, blood pressure, and prepares the body for fight or flight.

What is the primary function of the parasympathetic nervous system?

Calms body functions and assists in rest and digestion.

What triggers the release of adrenaline?

Activation of the sympathetic nervous system during stress.

What is the role of neurotransmitters?

They transmit signals across synapses between neurons.

What are catecholamines?

Hormones like epinephrine and norepinephrine released by the adrenal medulla.

How does the body maintain homeostasis during stress?

By regulating hormone release from the adrenal glands and activating the sympathetic nervous system.

What is diabetes insipidus?

A condition characterized by hyposecretion of ADH, leading to excessive urination.

What effect does alcohol have on ADH?

It inhibits its release, leading to increased urination.

What is the function of the hypothalamic-pituitary portal system?

To deliver hypothalamic hormones directly to the anterior pituitary.

What triggers the secretion of TSH?

The release of thyrotropin-releasing hormone (TRH) from the hypothalamus.

What is the role of thyroglobulin in thyroid hormone synthesis?

It acts as a precursor in the production of T3 and T4 thyroid hormones.

What is the significance of iodine in thyroid hormone production?

Iodine is essential for the synthesis of T3 and T4 hormones.

What condition is characterized by high levels of thyroid hormones?

Hyperthyroidism.

What does the hypothalamus control in relation to the pituitary gland?

It regulates its activity through releasing and inhibiting hormones.

What is the primary effect of growth hormone on muscles?

It increases amino acid uptake and protein synthesis.

What is the effect of prolonged stress on the body?

It can suppress the immune system and elevate blood sugar levels.

What is the relationship between the hypothalamus and the adrenal cortex?

The hypothalamus releases CRH which stimulates the adrenal cortex via ACTH.

Explain how negative feedback works in hormone regulation.

High hormone levels signal for decreased hormone production, maintaining balance.

What maintains the balance of calcium in the blood?

The parathyroid hormone (PTH) and calcitonin work antagonistically to regulate calcium levels.

What triggers the secretion of insulin?

High blood glucose levels.

What is the role of oxytocin during breastfeeding?

It stimulates milk ejection from the mammary glands.

What are the consequences of excessive growth hormone in adulthood?

Disproportionate growth of bones and tissues, known as acromegaly.

What is the primary hormone responsible for stress response in the body?

Cortisol, released by the adrenal cortex.

What effect does parathyroid hormone have on bones?

It stimulates the activity of osteoclasts to release calcium into the bloodstream.

How does aldosterone affect kidney function?

It promotes sodium retention and potassium excretion in the kidneys.

What hormonal changes occur during childbirth?

Increased levels of oxytocin facilitate uterine contractions.

What is the importance of the adrenal cortex's zona glomerulosa?

It primarily produces mineralocorticoids like aldosterone.

What is the hypothalamus's role in temperature regulation?

It helps regulate body temperature through hormone release.

What are the potential treatments for Addison's disease?

Corticosteroid replacement therapy.

How does the sympathetic nervous system prepare the body for action?

By increasing heart rate, blood pressure, and blood sugar levels.

What does diabetes insipidus lead to in terms of hydration status?

It leads to excessive urination and potential dehydration.

What hormones does the anterior pituitary secrete?

TSH, GH, ACTH, LH, FSH, and PRL.

What is the effect of parathyroid hormone on the intestines?

It increases calcium absorption from food.

What happens to adrenal hormone levels during prolonged stress?

They exhibit prolonged elevation due to continuous stimulation.

Name a function of thyroid hormones during growth periods.

They stimulate metabolic processes needed for growth and development.

What is the structure that connects the pituitary gland to the hypothalamus?

The infundibulum (pituitary stalk).