Endocrine System Overview

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Questions and Answers

Which hormone is responsible for stimulating milk synthesis?

Prolactin (correct)

Adrenocorticotropic hormone (ACTH)

Gonadotropic hormones

Thyroid stimulating hormone (TSH)

What is the primary effect of growth hormone on bones?

Stimulates proliferation of epiphyseal cartilage (correct)

Regulates blood sugar levels

Stimulates the production of thyroid hormones

Promotes fat metabolism

Which of the following is NOT a function of growth hormone?

Stimulating fat metabolism

Stimulating growth of long bones

Stimulating protein synthesis

Increasing insulin sensitivity (correct)

Which hormone stimulates the secretion and growth of the thyroid gland?

Thyroid stimulating hormone (TSH) Signup and view all the answers

The hypothalamus controls the secretion of anterior pituitary hormones through which mechanism?

Hypophysiotropic releasing and inhibiting hormones Signup and view all the answers

Growth hormone has which of the following metabolic effects?

Increased lipolysis Signup and view all the answers

What triggers the release of Thyrotropin releasing hormone (TRH)?

Decreased levels of thyroid hormones Signup and view all the answers

Which hormone is responsible for the maturation of ova and the synthesis of female sex hormones?

Follicle-stimulating hormone (FSH) Signup and view all the answers

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

To serve as a connection between the nervous system and the endocrine system. Signup and view all the answers

How are hormones synthesized in the posterior pituitary gland?

They are synthesized in the hypothalamus and transported. Signup and view all the answers

Which term describes the vascular connection between the hypothalamus and the anterior pituitary?

Hypothalamo-hypophysial portal circulation. Signup and view all the answers

What is the function of negative feedback in the endocrine system?

To prevent excessive hormone production by regulating its levels. Signup and view all the answers

The hypothalamus is influenced by signals from which of the following?

External factors and emotional stress responses. Signup and view all the answers

What type of feedback mechanisms exist between endocrine glands and the hypothalamus?

Short and long feedback loops. Signup and view all the answers

What type of cells are primarily responsible for hormone secretion in the hypothalamus?

Neurosecretory cells. Signup and view all the answers

Which gland is NOT included in the list of key components of the endocrine system?

Adrenal cortex. Signup and view all the answers

Study Notes

Endocrine System Overview

The endocrine system is a ductless gland system
Hormones are secreted directly into the bloodstream
Hormones reach target sites to exert their effects
The system helps regulate cellular metabolism, growth and development, and reproductive function
It also regulates blood sugar levels

Endocrine Glands

Endocrine glands are ductless glands releasing hormones directly into the blood
Hormones travel through blood to target locations to exert their function

Endocrine System Components

Hypothalamus
Pituitary gland (anterior and posterior)
Thymus gland
Thyroid gland
Pancreas
Adrenal glands
Reproductive system (ovaries and testes)

Hypothalamic-Pituitary Unit

The hypothalamus connects the nervous and endocrine systems
Posterior pituitary contains axons from hypothalamic neurons
Hypothalamic neurohormones travel via the portal system to anterior pituitary
Anterior pituitary hormones regulate other glands

Hypothalamic Connection with Pituitary Gland

Vascular connection between hypothalamus & anterior pituitary formed via a portal circulation
Nervous connection between hypothalamus & posterior pituitary through hypophysial tract

Hypothalamopituitary Connection

Neurosecretory cells in the hypothalamus produce releasing and inhibiting hormones
These hormones control anterior pituitary releases
Posterior pituitary hormones (ADH & oxytocin) are secreted by hypothalamic neurons

Control of Endocrine System

Negative feedback mechanisms regulate hormone levels
Short feedback loops involve the pituitary gland as a mediator
Long feedback loops involve target glands and the hypothalamus

Pituitary Gland

Site: Located at the base of the brain, within the sella turcica (a depression in the sphenoid bone)
Anterior pituitary hormones: TSH, ACTH, Gonadotrophins, GH and Prolactin
Posterior pituitary hormones: ADH, Oxytocin
Anterior pituitary hormones are critical in controlling other endocrine glands

Anterior Pituitary Hormones

Thyroid-stimulating hormone (TSH): Stimulates growth and secretion of thyroid gland
Adrenocorticotropic hormone (ACTH): Stimulates growth and secretion of adrenal gland
Growth hormone (GH): Stimulates growth of bones and tissues
Prolactin: Stimulates milk synthesis
Gonadotropins (FSH & LH): Stimulate maturation and sex hormone production

Growth Hormone Functions and Mechanism

Somatic growth: Stimulates bone growth & soft tissue development
Metabolic effects: Lipolysis, anti-insulin effect
Mechanism of action: Direct on cells and indirect via IGF-1 (somatomedin C) from the liver

Gigantism: Excessive GH secretion in childhood, resulting in excessively tall stature
Acromegaly: Excessive GH secretion in adulthood, resulting in disproportionately enlarged hands, feet, etc.

Pituitary Dwarfism

Insufficient GH secretion, resulting in short stature

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Description

This quiz covers the key components and functions of the endocrine system, including hormone secretion and the role of various glands like the hypothalamus and pituitary. Explore how hormones help regulate metabolism, growth, and reproductive functions within the body. Test your understanding of this vital system!