Quiz 7 Lab10 Endocrine System

This set of flashcards covers the comprehensive details of the endocrine system lecture, including hormonal regulation, feedback loops, anatomy, and pathology.

What is the primary function of the endocrine system?

To orchestrate a state of hormonal equilibrium within the body using widely distributed organs that work in a highly integrated manner.

How can endocrine diseases be broadly classified?

Diseases of underproduction, diseases of overproduction, or conditions involving the development of mass lesions.

Mass lesions in the endocrine system may be associated with what types of hormonal states?

Either underproduction or overproduction of hormones.

What is the first step recommended for studying the endocrine system?

Learning the glands, their hormones, and their regulation.

After learning the glands, what should be integrated into the study of the endocrine system?

Disease manifestations with diagnosis and management.

Define the term 'endocrine'.

Produces internal secretions that are transported around the body by the bloodstream.

Define the term 'paracrine'.

Describes a hormone or other secretion released from endocrine cells into the surrounding tissue rather than into the bloodstream.

Define the term 'exocrine'.

Produces external secretions that are released through a duct.

Which thyrotropin-related hormone is produced by the hypothalamus?

Thyrotropin-releasing hormone (TRH).

Which neurotransmitter that inhibits prolactin is produced by the hypothalamus?

Dopamine.

Which hypothalamic hormone stimulates the release of growth hormone?

Growth hormone-releasing hormone (GHRH).

Which hypothalamic hormone inhibits the release of growth hormone?

Somatostatin.

Which hypothalamic hormone regulates the release of FSH and LH?

Gonadotropin-releasing hormone (GnRH).

Which hypothalamic hormone is responsible for stimulating the release of ACTH?

Corticotropin-releasing hormone (CRH).

Which two hormones are produced in the hypothalamus but stored in the posterior pituitary?

Oxytocin and Vasopressin.

Identify the two principal hormones produced by the thyroid gland.

Triiodothyronine ($T_3$) and Thyroxine ($T_4$).

What hormone is produced by the pineal gland?

Melatonin.

Which hormones are listed as being secreted by the anterior pituitary?

Growth hormone (GH), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), and Prolactin.

What hormone is produced by the intermediate pituitary?

Melanocyte-stimulating hormone (MSH).

Besides Vasopressin, what is the other name for the hormone stored in the posterior pituitary that affects water retention?

Anti-diuretic hormone (ADH).

How are hormones transported from glands to regulate the body?

Directly into the bloodstream or transported along nerve tracts.

What mechanism does the endocrine system rely on to control hormone levels in the circulatory system?

Feedback mechanisms.

Define 'negative feedback'.

A system that prevents deviation from a mean value to maintain homoeostasis.

Define 'positive feedback'.

A system that promotes or facilitates deviation from a mean value.

What are thousands of systems in the human body designed to maintain?

Intra and extracellular environments.

What is 'feedforward' regulation also known as?

Adaptive regulation.

What is the approximate size of the pituitary gland?

The size of a pea.

Where is the pituitary gland located?

In a small, bony cavity at the base of the brain.

What are the primary functions influenced by the pituitary gland's secretions?

Other endocrine glands, growth, metabolism, and maturation.

Where is the hypothalamus located?

Below the thalamus, forming the basal portion of the diencephalon.

What does the hypothalamus regulate?

Body temperature, some metabolic processes, and the autonomic nervous system.

What is the hypophyseal portal system?

The system of blood vessels that link the hypothalamus and the anterior pituitary.

What is the alternative name for the anterior pituitary?

Adenohypophysis.

How many hormones does the anterior pituitary gland secrete according to Page 8?

7 hormones.

List the 7 hormones of the anterior pituitary mentioned on Page 8.

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, endorphins, and growth hormone (GH).

What is the function of neurosecretory cells in the hypothalamus regarding the anterior pituitary?

They produce releasing and release-inhibiting hormones that are secreted into a portal system.

What physiological processes are regulated by the anterior pituitary?

Processes including stress, growth, reproduction, and lactation.

What is the destination of ADH and oxytocin after they leave the neurosecretory cells in the hypothalamus?

They move down axons to axon endings in the posterior pituitary.

What is the target organ for follicle-stimulating hormone (FSH) and luteinizing hormone (LH)?

Ovaries and testes.

What are the target tissues for growth hormone (GH)?

Bones and tissues.

What is the target organ for prolactin (PRL)?

Mammary glands.

What is the target for adrenocorticotropic hormone (ACTH)?

Adrenal cortex.

What is the target for thyroid-stimulating hormone (TSH)?

Thyroid gland.

What is the target for antidiuretic hormone (ADH)?

Kidney tubules.

What are the target tissues for oxytocin (OT)?

Smooth muscle in the uterus and mammary glands.

Which hypothalamic nuclei synthesize oxytocin and ADH?

Paraventricular nucleus and Supraoptic nucleus.

What is the name of the tract through which oxytocin and ADH are transported to the posterior pituitary?

The hypothalamic-hypophyseal tract.

What triggers the release of oxytocin or ADH from the axon terminals into the blood?

Action potentials arriving at the axon terminals when hypothalamic neurons fire.

What is the purpose of most endocrine glands being under negative feedback control?

To maintain homoeostasis and prevent deviation from an ideal value.

What metabolic hormone serves as a key example of a negative feedback system?

Thyroxine.

Which thyroid hormone has the greatest metabolic activity?

Triiodothyronine ($T_3$).

What does the thyroid gland produce that plays a role in calcium homeostasis?

Calcitonin.

What hormone from the anterior pituitary regulates hormonal output from the thyroid?

Thyroid-stimulating hormone (TSH).

What hormone from the hypothalamus regulates TSH production?

Thyrotropin-releasing hormone (TRH).

What signals the hypothalamus to stop secreting TRH (and thus stops TSH)?

Increased levels of thyroid hormones ($T_3$ and $T_4$).

What is the functional unit shown for thyroid hormone formation in Page 14?

The Thyroid Follicle.

What protein found in the colloid is essential for thyroid hormone formation?

Thyroglobulin.

What are the two components that combine to form thyroid hormones?

Iodine and Tyrosine.

What is formed by the combination of thyroglobulin and two iodine molecules?

Diiodotyrosine.

What is formed by the combination of thyroglobulin and one iodine molecule?

Monoiodotyrosine.

What is the typical ratio/percentage of Thyroxine ($T_4$) produced by the thyroid?

90\text{%}.

What is the typical percentage of Triiodothyronine ($T_3$) produced by the thyroid?

10\text{%}.

What effect does a dietary iodine deficiency have on thyroid hormone production?

The thyroid will not be able to make thyroid hormone.

How does a lack of thyroid hormone affect the pituitary?

It leads to decreased negative feedback, which in turn increases production of thyroid-stimulating hormone (TSH).

What is 'goiter'?

An enlarged thyroid gland caused by increased TSH levels due to iodine deficiency.

What is the biological compensation provided by an endemic colloid goiter?

It increases the thyroid’s ability to trap more iodide to produce adequate thyroid hormone.

List ocular symptoms of hyperthyroidism.

Dryness, corneal erosion, pain in the eyes, and lacrimation.

List psychological symptoms of hyperthyroidism.

Irritability, anxiety, depression, and insomnia.

What common hair and skin symptoms are associated with hyperthyroidism?

Sweating and early gray hair.

What cardiac symptoms are associated with hyperthyroidism?

Heart rhythm disorder and tachycardia.

What urinary symptoms are associated with hyperthyroidism?

Thirst and copious urination.

List reproductive symptoms for hyperthyroidism.

Infertility, meager menstruation, and decreased potency.

What musculoskeletal symptoms occur in hyperthyroidism?

Hypotrophy of muscles, tremors in the body and limbs, and development of osteoporosis.

What gastrointestinal symptoms are associated with hyperthyroidism?

Increased appetite, indigestion, diarrhea, and abdominal pain.

How does hair change in cases of hypothyroidism?

Thinning hair and hair loss, including loss of eyebrow hair.

What are the facial and skin symptoms of hypothyroidism?

Puffy face and dry, coarse skin.

What is the characteristic heartbeat in hypothyroidism?

Slow heartbeat.

What gastrointestinal symptom is common in hypothyroidism?

Constipation.

What temperature-related symptom is characteristic of hypothyroidism?

Intolerance to cold and cool extremities.

How does weight usually change in hypothyroidism?

Weight gain.

What neurological/cognitive symptoms occur in hypothyroidism?

Poor memory and a feeling of tiredness.

Contrast menstruation in hyperthyroidism vs. hypothyroidism.

Hyperthyroidism has meager menstruation; hypothyroidism has heavy menstruation.

What nerve syndrome is associated with hypothyroidism?

Carpal tunnel syndrome.

What do positive feedback mechanisms control?

Self-perpetuating events.

What is a key example of positive feedback in the human body?

Childbirth.

During the positive feedback loop for milk ejection, what stimulates the nerves in the breasts?

Suckling.

Which part of the pituitary releases oxytocin during the milk ejection feedback loop?

Posterior pituitary.

What do the muscle cells in the milk gland do in response to oxytocin?

Contract and squeeze out milk.

What is another name for Growth Hormone (GH)?

Somatotropin.

How does Growth Hormone affect linear growth and muscle mass?

Through IGF-1 (somatomedin C) secretion by the liver.

What metabolic effect does GH have on insulin?

It increases insulin resistance (diabetogenic effect).

When is Growth Hormone released in pulses?

In response to Growth hormone-releasing hormone (GHRH).

List five conditions under which GH secretion increases.

Exercise, deep sleep, puberty, hypoglycemia, and CKD (Chronic Kidney Disease).

List three factors that inhibit GH secretion.

Glucose, somatostatin, and somatomedin.

What is somatomedin?

A regulatory molecule secreted by the liver in response to GH acting on target tissues.

What are the effects of GH on protein and DNA?

Increased protein synthesis and increased DNA and RNA synthesis.

How does GH affect cellular development?

It increases cell size and number.

What connective tissue components are increased by GH?

Chondroitin sulfate and collagen.

What are the effects of IGF-1 on amino acids and glucose?

Increased amino acid uptake and decreased glucose uptake.

What is the effect of GH on fat?

Increased lipolysis.