Week 2: The Endocrine System Flashcards
Definition
Hormones produced by the adrenal medulla that prepare the body for a “fight or flight” response by increasing heart rate, blood pressure, and glucose levels.
Define
Adrenaline/Noradrenaline
Define
Hypersecretion
The excessive production of hormones by a gland.
Define
Hypothalamic-Pituitary-Adrenal Axis (HPA Axis)
A feedback loop involving the hypothalamus, pituitary gland, and adrenal glands that regulates cortisol production.
Define
Hypothalamic-Pituitary-Thyroid Axis (HPT Axis)
A feedback loop involving the hypothalamus, pituitary gland, and thyroid gland that regulates thyroid hormone production.
Definition
The outer part of the adrenal glands that produces corticosteroids, including cortisol and aldosterone.
Define
Adrenal Cortex
Definition
The insufficient production of hormones by a gland.
Hyposecretion
Define
Endocrine System
A system of glands that secrete hormones directly into the bloodstream to regulate various bodily functions.
Define
Luteinising Hormone (LH)
A hormone produced by the anterior pituitary gland that triggers ovulation in females and stimulates testosterone production in males.
Definition
A brain region that regulates the endocrine system by controlling the release of hormones from the pituitary gland.
Define
Hypothalamus
Definition
Hormones produced by the thyroid gland that include thyroxine (T4) and triiodothyronine (T3).
Define
Thyroid Hormones (TH)
Definition
A hormone produced by the ovaries that prepares the uterus for pregnancy and regulates the menstrual cycle.
Define
Progesterone
Define
Testosterone
A hormone primarily produced by the testes that regulates male reproductive tissues, secondary sexual characteristics, and promotes muscle and bone growth.
Define
Erythropoietin (EPO)
A hormone produced by the kidneys that stimulates red blood cell production in the bone marrow.
Definition
Receptors located on the cell surface that bind to amino acid-based hormones and initiate intracellular signaling pathways.
Define
Plasma Membrane Receptors
Define
Plasma Membrane Receptors
Receptors located on the cell surface that bind to amino acid-based hormones and initiate intracellular signaling pathways.
Definition
The narrowing of blood vessels, which increases blood pressure and reduces blood flow.
Define
Vasoconstriction
Definition
A feedback loop involving the hypothalamus, pituitary gland, and thyroid gland that regulates thyroid hormone production.
Define
Hypothalamic-Pituitary-Thyroid Axis (HPT Axis)
Definition
The release of hormones in response to neural impulses.
Define
Neural Stimulus
Define
Metabolic Rate
The rate at which the body expends energy, influenced by various hormones.
Definition
The breakdown of glycogen into glucose in the liver and muscle tissues.
Define
Glycogenolysis
Definition
A hormone produced by the anterior pituitary gland that stimulates the growth of ovarian follicles in females and spermatogenesis in males.
Define
Follicle-Stimulating Hormone (FSH)
Define
Neural Stimulus
The release of hormones in response to neural impulses.
Define
Hormones
Chemical messengers produced by glands that travel through the bloodstream to regulate various physiological processes.
Definition
A hormone produced by the adrenal cortex that helps regulate metabolism, reduces inflammation, and assists in the body’s stress response.
Define
Cortisol
Definition
A hormone produced by the anterior pituitary gland that stimulates milk production in the mammary glands.
Define
Prolactin
Definition
The stalk that connects the hypothalamus to the pituitary gland.
Define
Infundibulum
Definition
A hormone produced by the parathyroid glands that increases blood calcium levels by promoting bone resorption and increasing calcium absorption in the intestines.
Define
Parathyroid Hormone (PTH)
Define
Parathyroid Hormone (PTH)
A hormone produced by the parathyroid glands that increases blood calcium levels by promoting bone resorption and increasing calcium absorption in the intestines.
Define
Aldosterone
A hormone produced by the adrenal cortex that helps regulate blood pressure by increasing sodium reabsorption in the kidneys.
Define
Infundibulum
The stalk that connects the hypothalamus to the pituitary gland.
Define
Amino Acid-Based Hormones
Hormones derived from amino acids that bind to plasma membrane receptors and trigger responses inside the cell.
Define
Hypothalamic-Hypophyseal Tract
The neural pathway that connects the hypothalamus to the posterior pituitary.
Definition
A hormone produced by the pancreas that lowers blood glucose levels by facilitating the uptake of glucose into cells.
Define
Insulin
Define
Nervous System
The system of nerves and cells that transmits signals between different parts of the body, influencing the endocrine system’s activity.
Define
Hyposecretion
The insufficient production of hormones by a gland.
Definition
Processes that use the output of a system to regulate its own activity, often through negative feedback to maintain homeostasis.
Define
Feedback Mechanisms
Definition
A hormone produced by the thyroid gland that lowers blood calcium levels by inhibiting bone resorption.
Define
Calcitonin
Definition
A hormone primarily produced by the ovaries that regulates the menstrual cycle, supports reproductive tissues, and influences secondary sexual characteristics in females.
Define
Oestrogen
Definition
The release of hormones in response to changes in blood levels of certain ions or nutrients.
Define
Humoral Stimulus
Define
Steroid Hormones
Hormones derived from cholesterol that pass through cell membranes and act on intracellular receptors.
Define
Feedback Mechanisms
Processes that use the output of a system to regulate its own activity, often through negative feedback to maintain homeostasis.
Define
Progesterone
A hormone produced by the ovaries that prepares the uterus for pregnancy and regulates the menstrual cycle.
Define
Thyroid-Stimulating Hormone (TSH)
A hormone produced by the anterior pituitary gland that stimulates the thyroid gland to produce thyroid hormones.
Define
Oxytocin
A hormone produced by the posterior pituitary gland that stimulates uterine contractions during childbirth and the release of milk from the mammary glands.
Define
Anterior Pituitary
The front part of the pituitary gland that produces and secretes various hormones, including FSH, LH, and GH.
Definition
Chemical messengers produced by glands that travel through the bloodstream to regulate various physiological processes.
Define
Hormones
Definition
A hormone produced by the anterior pituitary gland that stimulates growth and cell reproduction.
Define
Growth Hormone (GH)
Define
Glucagon
A hormone produced by the pancreas that raises blood glucose levels by promoting glycogen breakdown in the liver.
Define
Glycogenolysis
The breakdown of glycogen into glucose in the liver and muscle tissues.
Definition
A feedback loop involving the hypothalamus, pituitary gland, and adrenal glands that regulates cortisol production.
Define
Hypothalamic-Pituitary-Adrenal Axis (HPA Axis)
Definition
The rate at which the body expends energy, influenced by various hormones.
Define
Metabolic Rate
Definition
A hormone produced by the anterior pituitary gland that triggers ovulation in females and stimulates testosterone production in males.
Define
Luteinising Hormone (LH)
Define
Intracellular Receptors
Receptors located inside the cell that bind to steroid hormones and influence gene expression.
Definition
Hormones derived from cholesterol that pass through cell membranes and act on intracellular receptors.
Define
Steroid Hormones
Definition
A system of glands that secrete hormones directly into the bloodstream to regulate various bodily functions.
Define
Endocrine System
Definition
The front part of the pituitary gland that produces and secretes various hormones, including FSH, LH, and GH.
Define
Anterior Pituitary
Define
Vasoconstriction
The narrowing of blood vessels, which increases blood pressure and reduces blood flow.
Definition
A hormone produced by the anterior pituitary gland that stimulates the adrenal cortex to produce cortisol.
Define
Adrenocorticotropic Hormone (ACTH)
Define
Adrenaline/Noradrenaline
Hormones produced by the adrenal medulla that prepare the body for a “fight or flight” response by increasing heart rate, blood pressure, and glucose levels.
Definition
Glands that secrete hormones directly into the bloodstream.
Define
Endocrine Glands
Define
Humoral Stimulus
The release of hormones in response to changes in blood levels of certain ions or nutrients.
Define
Prolactin
A hormone produced by the anterior pituitary gland that stimulates milk production in the mammary glands.
Definition
A hormone primarily produced by the testes that regulates male reproductive tissues, secondary sexual characteristics, and promotes muscle and bone growth.
Define
Testosterone
Define
Adrenal Medulla
The inner part of the adrenal glands that produces adrenaline and noradrenaline.
Define
Hypothalamus
A brain region that regulates the endocrine system by controlling the release of hormones from the pituitary gland.
Define
Gluconeogenesis
The production of glucose from non-carbohydrate sources in the liver.
Define
Adrenocorticotropic Hormone (ACTH)
A hormone produced by the anterior pituitary gland that stimulates the adrenal cortex to produce cortisol.
Definition
A hormone produced by the pancreas that raises blood glucose levels by promoting glycogen breakdown in the liver.
Define
Glucagon
Definition
A hormone produced by the kidneys that stimulates red blood cell production in the bone marrow.
Define
Erythropoietin (EPO)
Definition
A hormone produced by the posterior pituitary gland that stimulates uterine contractions during childbirth and the release of milk from the mammary glands.
Define
Oxytocin
Define
Thyroid Hormones (TH)
Hormones produced by the thyroid gland, including thyroxine (T4) and triiodothyronine (T3), that regulate metabolism, growth, and development.
Define
Calcitonin
A hormone produced by the thyroid gland that lowers blood calcium levels by inhibiting bone resorption.
Define
Insulin
A hormone produced by the pancreas that lowers blood glucose levels by facilitating the uptake of glucose into cells.
Define
Negative Feedback
A mechanism where the output of a system reduces the effect of the initial stimulus, helping to maintain equilibrium.
Definition
The back part of the pituitary gland that stores and releases hormones produced by the hypothalamus, including ADH and oxytocin.
Define
Posterior Pituitary
Define
Posterior Pituitary
The back part of the pituitary gland that stores and releases hormones produced by the hypothalamus, including ADH and oxytocin.
Definition
A mechanism where the output of a system reduces the effect of the initial stimulus, helping to maintain equilibrium.
Define
Negative Feedback
Define
Follicle-Stimulating Hormone (FSH)
A hormone produced by the anterior pituitary gland that stimulates the growth of ovarian follicles in females and spermatogenesis in males.
Definition
The release of hormones in response to other hormones.
Define
Hormonal Stimulus
Definition
A hormone produced by the posterior pituitary gland that helps regulate water balance in the body by increasing water reabsorption in the kidneys.
Define
Antidiuretic Hormone (ADH)
Define
Thyroid Hormones (TH)
Hormones produced by the thyroid gland that include thyroxine (T4) and triiodothyronine (T3).
Definition
A system of blood vessels that connects the hypothalamus and anterior pituitary, allowing hormones to travel directly between these regions.
Define
Hypophyseal Portal System
Define
Hormonal Stimulus
The release of hormones in response to other hormones.
Definition
The excessive production of hormones by a gland.
Define
Hypersecretion
Definition
The maintenance of a stable internal environment within the body despite external changes.
Define
Homeostasis
Definition
A hormone produced by the anterior pituitary gland that stimulates the thyroid gland to produce thyroid hormones.
Define
Thyroid-Stimulating Hormone (TSH)
Define
Endocrine Glands
Glands that secrete hormones directly into the bloodstream.
Define
Antidiuretic Hormone (ADH)
A hormone produced by the posterior pituitary gland that helps regulate water balance in the body by increasing water reabsorption in the kidneys.
Definition
The production of glucose from non-carbohydrate sources in the liver.
Define
Gluconeogenesis
Definition
The system of nerves and cells that transmits signals between different parts of the body, influencing the endocrine system’s activity.
Define
Nervous System
Definition
Hormones produced by the thyroid gland, including thyroxine (T4) and triiodothyronine (T3), that regulate metabolism, growth, and development.
Define
Thyroid Hormones (TH)
Define
Adrenal Cortex
The outer part of the adrenal glands that produces corticosteroids, including cortisol and aldosterone.
Definition
Hormones derived from amino acids that bind to plasma membrane receptors and trigger responses inside the cell.
Define
Amino Acid-Based Hormones
Definition
The neural pathway that connects the hypothalamus to the posterior pituitary.
Define
Hypothalamic-Hypophyseal Tract
Definition
Receptors located inside the cell that bind to steroid hormones and influence gene expression.
Define
Intracellular Receptors
Define
Cortisol
A hormone produced by the adrenal cortex that helps regulate metabolism, reduces inflammation, and assists in the body’s stress response.
Definition
The inner part of the adrenal glands that produces adrenaline and noradrenaline.
Define
Adrenal Medulla
Define
Hypophyseal Portal System
A system of blood vessels that connects the hypothalamus and anterior pituitary, allowing hormones to travel directly between these regions.
Define
Homeostasis
The maintenance of a stable internal environment within the body despite external changes.
Define
Oestrogen
A hormone primarily produced by the ovaries that regulates the menstrual cycle, supports reproductive tissues, and influences secondary sexual characteristics in females.
Definition
A hormone produced by the adrenal cortex that helps regulate blood pressure by increasing sodium reabsorption in the kidneys.
Define
Aldosterone
Define
Growth Hormone (GH)
A hormone produced by the anterior pituitary gland that stimulates growth and cell reproduction.
Why is it important for health professionals to understand the endocrine system?
Understanding the endocrine system is crucial for health professionals to diagnose and treat endocrine disorders such as diabetes mellitus, Grave’s disease, Hypothyroidism, Addison’s disease, Cushing’s syndrome, and Gigantism, as well as to understand the medical treatments available for these conditions.
What are some common endocrine disorders?
Common endocrine disorders include diabetes mellitus, Grave’s disease, Hypothyroidism, Addison’s disease, Cushing’s syndrome, and Gigantism.
How do head injuries, tumours, ageing, genetic abnormalities, and autoimmune diseases affect the endocrine system?
These conditions can result in endocrine disorders that disrupt normal body functions and impact life expectancy.
What are the two communication systems that regulate body functions?
The nervous system and the endocrine system.
How does the nervous system respond to a stimulus?
The nervous system responds quickly (milliseconds) by generating and conducting electrical signals along neurons to alter the activities of an effector, such as a muscle or gland.
How does the endocrine system respond to a stimulus?
The endocrine system responds more slowly (minutes) by producing and secreting hormones into the bloodstream to alter the activities of cells with the appropriate hormone receptors.
What is the role of hormones in the endocrine system?
Hormones are chemical messengers that regulate various body functions by altering the activities of cells that have the appropriate hormone receptors.
What is the main difference in response time between the nervous and endocrine systems?
The nervous system responds in milliseconds, while the endocrine system responds in minutes.
What is homeostasis?
Homeostasis is the process by which the body maintains a stable internal environment despite changes in external conditions.
How do the nervous and endocrine systems work together to maintain homeostasis?
The nervous system provides rapid, short-term responses through electrical signals, while the endocrine system offers slower, longer-lasting regulation through hormones to maintain balance in the body.
Why might a health professional need to know about hormonal treatments?
Hormonal treatments may be necessary to manage and treat endocrine disorders and restore balance in hormone levels.
What are the effects of endocrine disorders on life expectancy?
Endocrine disorders can dramatically impact normal body functions and potentially reduce life expectancy if not properly managed.
What role does the endocrine system play in regulating body functions?
The endocrine system regulates body functions by releasing hormones that influence the activity of various cells and organs to maintain balance and homeostasis.
What is the significance of hormone receptors in the endocrine system?
Hormone receptors on cells are crucial because they allow hormones to bind and exert their effects, influencing the cell’s activity.
Name a few conditions where endocrine disorders might require medical treatment.
Conditions include diabetes mellitus, Grave’s disease, Hypothyroidism, Addison’s disease, Cushing’s syndrome, and Gigantism.
How are hormones secreted by endocrine glands?
Hormones are secreted in response to stimuli such as hormonal signals, changes in blood ion or nutrient levels, and signals from the nervous system.
What are the three main categories of stimuli that trigger hormone secretion?
Hormonal stimulus
Humoral stimulus
Neural stimulus
What is a hormonal stimulus?
A hormonal stimulus occurs when one hormone stimulates the secretion of another hormone.
What is a humoral stimulus?
A humoral stimulus involves changes in ion or nutrient blood levels, such as glucose, calcium (Ca2+), sodium (Na+), or potassium (K+).
What is a neural stimulus?
A neural stimulus involves signals from the nervous system that trigger hormone secretion.
How do feedback mechanisms regulate hormone secretion?
Negative feedback mechanisms regulate hormone secretion by returning hormone levels and blood levels to normal when homeostasis is restored.
What are the two chemical classifications of hormones?
Steroid hormones
Amino acid-based hormones
What are steroid hormones made from?
Steroid hormones are made from cholesterol.
How do steroid hormones interact with target cells?
Steroid hormones are lipid-soluble, can easily diffuse across the plasma membrane, and bind to intracellular receptors inside the cell.
What are amino acid-based hormones composed of?
Amino acid-based hormones can be single amino acids, peptides, or proteins.
How do amino acid-based hormones interact with target cells?
Amino acid-based hormones are lipid-insoluble, cannot easily diffuse across the plasma membrane, and bind to receptors embedded in the plasma membrane.
What is the role of receptors in hormone action?
Receptors bind to hormones and trigger a response in the target cell, which depends on both the hormone and the target cell type.
What are some effects of hormone action?
Activating or deactivating enzymes
Changing the permeability of the plasma membrane
Stimulating protein synthesis
Inducing cell secretory activity
Stimulating cell division
How do hormones alter target cell activity?
Hormones alter target cell activity by controlling metabolic reactions, facilitating transportation of substances, regulating fluid and electrolyte balance, blood pressure, reproductive functions, development, and growth, and maintaining homeostasis.
How do hormones from the hypothalamus reach the posterior pituitary gland?
Hormones produced by the hypothalamus travel down the axons of neurons through the hypothalamic-hypophyseal tract to the posterior pituitary, where they are stored and later secreted.
How do hormones from the hypothalamus reach the anterior pituitary gland?
Hypothalamic neurons secrete releasing or inhibiting hormones into the hypophyseal portal system, which transports these hormones through the infundibulum to the anterior pituitary.
What is the main action of Antidiuretic Hormone (ADH)?
ADH decreases urine output by increasing water reabsorption in the kidneys, thereby diluting blood plasma and restoring normal blood volume and pressure.
What is the stimulus for the secretion of ADH?
ADH is secreted when blood sodium levels increase or blood volume and pressure decrease.
What is the main action of Oxytocin?
Oxytocin stimulates uterine contractions during labor and milk ejection during breastfeeding.
What stimulates the secretion of Oxytocin?
The stretching of the uterus during labor and the suckling action of an infant during breastfeeding stimulate the secretion of oxytocin.
Where is Growth Hormone (GH) produced and what are its main actions?
GH is produced by the anterior pituitary. It promotes growth of body tissues, stimulates protein synthesis, and increases cell division and growth, particularly in the liver, skeletal muscles, and bones.
What hormones regulate the secretion of Growth Hormone (GH)?
Growth hormone-releasing hormone (GHRH) stimulates GH secretion, while Growth hormone-inhibiting hormone (GHIH or somatostatin) inhibits it.
What are the main actions of Thyroid Hormones (T3 and T4)?
Thyroid hormones increase basal metabolic rate, body heat production, heart rate, force of contraction, and promote growth of muscles and bones, and nervous system development.
What stimulates the secretion of Thyroid Hormones (TH)?
Thyrotropin-releasing hormone (TRH) from the hypothalamus stimulates the secretion of thyroid hormones by the thyroid gland.
What is the main action of Calcitonin?
Calcitonin decreases blood calcium levels by inhibiting osteoclast activity and stimulating calcium uptake into bone.
What stimulates the secretion of Calcitonin?
Calcitonin is secreted when blood calcium levels increase above normal.
What is the main action of Parathyroid Hormone (PTH)?
PTH increases blood calcium levels by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and promoting calcium absorption in the intestines.
What stimulates the secretion of Parathyroid Hormone (PTH)?
PTH is secreted when blood calcium levels decrease below the normal range.
What is the main action of Insulin?
Insulin lowers blood glucose levels by promoting glucose uptake into cells and its storage as glycogen in the liver and muscle.
What is the main action of Glucagon?
Glucagon increases blood glucose levels by stimulating glycogen breakdown in the liver and promoting glucose release into the bloodstream.
What are the main actions of Cortisol?
Cortisol increases blood glucose levels through gluconeogenesis, reduces inflammation, and helps the body respond to stress.
What is the main action of Aldosterone?
Aldosterone increases sodium reabsorption in the kidneys, which in turn increases water retention and blood pressure.
What are the main actions of Adrenaline and Noradrenaline?
Adrenaline and Noradrenaline increase heart rate, blood pressure, and blood glucose levels, preparing the body for a ‘fight or flight’ response.
What are the main actions of Oestrogen?
Oestrogen regulates the menstrual cycle, promotes development of female secondary sexual characteristics, and supports reproductive tissues.
What are the main actions of Progesterone?
Progesterone prepares the uterus for implantation of a fertilized egg and helps maintain pregnancy.
What are the main actions of Testosterone?
Testosterone promotes the development of male secondary sexual characteristics, stimulates sperm production, and supports muscle and bone growth.
Where is Antidiuretic Hormone (ADH) produced and secreted?
ADH is produced in the hypothalamus and secreted by the posterior pituitary gland.
What stimulates the secretion of Antidiuretic Hormone (ADH)?
ADH secretion is stimulated by increased blood sodium levels or decreased blood volume and blood pressure.
What are the target organs or cells for Antidiuretic Hormone (ADH)?
The target organs for ADH are the kidneys.
What is the main action of Antidiuretic Hormone (ADH)?
ADH decreases urine output by increasing water reabsorption in the kidneys.
Where is Oxytocin produced and secreted?
Oxytocin is produced in the hypothalamus and secreted by the posterior pituitary gland.
What stimulates the secretion of Oxytocin?
Oxytocin secretion is stimulated by the stretching of the uterus during labor and the suckling of an infant during breastfeeding.
What are the target organs or cells for Oxytocin?
The target organs for Oxytocin are the uterus and mammary glands.
What is the main action of Oxytocin?
Oxytocin stimulates uterine contractions during labor and milk ejection during breastfeeding.
Where is Growth Hormone (GH) produced and secreted?
GH is produced and secreted by the anterior pituitary gland.
What stimulates the secretion of Growth Hormone (GH)?
GH secretion is stimulated by Growth Hormone-Releasing Hormone (GHRH) and inhibited by Growth Hormone-Inhibiting Hormone (GHIH).
What are the target organs or cells for Growth Hormone (GH)?
The target organs for GH include the liver, skeletal muscles, and bones.
What is the main action of Growth Hormone (GH)?
GH promotes growth of body tissues, stimulates protein synthesis, and increases cell division and growth.
Where are Thyroid Hormones (T3 and T4) produced and secreted?
Thyroid hormones are produced and secreted by the thyroid gland.
What stimulates the secretion of Thyroid Hormones (T3 and T4)?
Thyroid-stimulating Hormone (TSH) from the anterior pituitary stimulates the secretion of T3 and T4.
What are the target organs or cells for Thyroid Hormones (T3 and T4)?
Thyroid hormones target virtually every cell in the body.
What are the main actions of Thyroid Hormones (T3 and T4)?
Thyroid hormones increase basal metabolic rate, body heat production, heart rate, and promote growth of muscles and bones.
Where is Calcitonin produced and secreted?
Calcitonin is produced and secreted by the parafollicular cells of the thyroid gland.
What stimulates the secretion of Calcitonin?
Calcitonin secretion is stimulated by increased blood calcium levels.
What are the target organs or cells for Calcitonin?
The target organs for Calcitonin are bones.
What is the main action of Calcitonin?
Calcitonin decreases blood calcium levels by inhibiting osteoclast activity and promoting calcium uptake into bones.
Where is Parathyroid Hormone (PTH) produced and secreted?
PTH is produced and secreted by the parathyroid glands.
What stimulates the secretion of Parathyroid Hormone (PTH)?
PTH secretion is stimulated by decreased blood calcium levels.
What are the target organs or cells for Parathyroid Hormone (PTH)?
The target organs for PTH include bones, kidneys, and the small intestines.
What is the main action of Parathyroid Hormone (PTH)?
PTH increases blood calcium levels by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and promoting calcium absorption in the intestines.
Where is Insulin produced and secreted?
Insulin is produced and secreted by the beta cells of the pancreas.
What stimulates the secretion of Insulin?
Insulin secretion is stimulated by increased blood glucose levels.
What are the target organs or cells for Insulin?
The target organs for Insulin include the liver, muscle, and fat cells.
Where is Glucagon produced and secreted?
Glucagon is produced and secreted by the alpha cells of the pancreas.
What is the main action of Insulin?
Insulin lowers blood glucose levels by facilitating glucose uptake into cells and promoting its storage as glycogen.
What stimulates the secretion of Glucagon?
Glucagon secretion is stimulated by decreased blood glucose levels.
What are the target organs or cells for Glucagon?
The target organs for Glucagon are the liver and, to a lesser extent, the adipose tissue.
What is the main action of Glucagon?
Glucagon increases blood glucose levels by promoting glycogen breakdown and glucose release from the liver.
Cortisol
Cortisol is produced and secreted by the adrenal cortex.
What stimulates the secretion of Cortisol?
Cortisol secretion is stimulated by Adrenocorticotropic Hormone (ACTH) from the anterior pituitary.
What are the target organs or cells for Cortisol?
The target organs for Cortisol include the liver, muscles, and immune system.
What is the main action of Cortisol?
Cortisol increases blood glucose levels through gluconeogenesis, reduces inflammation, and helps the body respond to stress.
Where is Aldosterone produced and secreted?
Aldosterone is produced and secreted by the adrenal cortex.
What stimulates the secretion of Aldosterone?
Aldosterone secretion is stimulated by increased blood potassium levels and the renin-angiotensin system.
What are the target organs or cells for Aldosterone?
The target organs for Aldosterone are the kidneys.
What is the main action of Aldosterone?
Aldosterone increases sodium reabsorption in the kidneys, which promotes water retention and increases blood pressure.
Where are Adrenaline and Noradrenaline produced and secreted?
Adrenaline and Noradrenaline are produced and secreted by the adrenal medulla.
What stimulates the secretion of Adrenaline and Noradrenaline?
Their secretion is stimulated by the sympathetic nervous system during stress or danger.
What are the target organs or cells for Adrenaline and Noradrenaline?
The target organs include the heart, blood vessels, and lungs.
What are the main actions of Adrenaline and Noradrenaline?
Adrenaline and Noradrenaline increase heart rate, blood pressure, and blood glucose levels, preparing the body for a ‘fight or flight’ response.
Where is Oestrogen produced and secreted?
Oestrogen is primarily produced and secreted by the ovaries.
What stimulates the secretion of Oestrogen?
Oestrogen secretion is stimulated by Follicle-Stimulating Hormone (FSH) and Luteinising Hormone (LH) from the anterior pituitary.
What are the target organs or cells for Oestrogen?
The target organs for Oestrogen include the uterus, breasts, and bones.
What are the main actions of Oestrogen?
Oestrogen regulates the menstrual cycle, promotes development of female secondary sexual characteristics, and supports reproductive tissues.
Where is Progesterone produced and secreted?
Progesterone is primarily produced and secreted by the ovaries and the placenta during pregnancy.
What stimulates the secretion of Progesterone?
Progesterone secretion is stimulated by Luteinising Hormone (LH) from the anterior pituitary.
What are the target organs or cells for Progesterone?
The target organs for Progesterone are the uterus and mammary glands.
What is the main action of Progesterone?
Progesterone prepares the uterus for implantation of a fertilized egg and helps maintain pregnancy.
Where is Testosterone produced and secreted?
Testosterone is produced and secreted by the testes in males and, in smaller amounts, by the ovaries in females.
What are the target organs or cells for Testosterone?
The target organs for Testosterone include the testes, muscles, and bones.
What stimulates the secretion of Testosterone?
Testosterone secretion is stimulated by Luteinising Hormone (LH) and Follicle-Stimulating Hormone (FSH) from the anterior pituitary.
What are the main actions of Testosterone?
Testosterone promotes the development of male secondary sexual characteristics, stimulates sperm production, and supports muscle and bone growth.
Where is Prolactin produced and secreted?
Prolactin is produced and secreted by the anterior pituitary gland.
What is the stimulus for Prolactin secretion?
The stimulus for Prolactin secretion is a decrease in Prolactin-inhibiting hormone (PIH) from the hypothalamus.
What are the target organs or cells of Prolactin?
The target organ of Prolactin is the mammary glands.
What are the main actions of Prolactin?
Prolactin stimulates milk production in the mammary glands. Its role in males is not well understood.
Where is Follicle-Stimulating Hormone (FSH) produced and secreted?
FSH is produced and secreted by the anterior pituitary gland.
What is the stimulus for FSH secretion?
The stimulus for FSH secretion is Follicle-stimulating hormone-releasing hormone (GnRH) from the hypothalamus.
What are the target organs or cells of FSH?
The target organs of FSH are the ovaries in females and the testes in males.
What are the main actions of FSH?
In females, FSH stimulates the development of ovarian follicles and the production of estrogen. In males, FSH regulates sperm production.
Where is Luteinizing Hormone (LH) produced and secreted?
LH is produced and secreted by the anterior pituitary gland.
What is the stimulus for LH secretion?
The stimulus for LH secretion is Luteinizing hormone-releasing hormone (GnRH) from the hypothalamus.
What are the target organs or cells of LH?
The target organs of LH are the ovaries in females and the testes in males.
What are the main actions of LH?
In females, LH stimulates ovulation and the production of progesterone and estrogen. In males, LH stimulates the production and secretion of testosterone.
Where is Adrenocorticotropic Hormone (ACTH) produced and secreted?
ACTH is produced and secreted by the anterior pituitary gland.
What is the stimulus for ACTH secretion?
The stimulus for ACTH secretion is Corticotropin-releasing hormone (CRH) from the hypothalamus.
What are the target organs or cells of ACTH?
The target organ of ACTH is the adrenal cortex.
What are the main actions of ACTH?
ACTH stimulates the adrenal cortex to secrete cortisol.
Where is Erythropoietin (EPO) produced and secreted?
Erythropoietin is produced and secreted primarily by the kidneys. It is also produced in small amounts by the liver.
What is the stimulus for EPO secretion?
The stimulus for EPO secretion is decreased oxygen levels (hypoxia) in the blood.
What are the target organs or cells of EPO?
The target organs of EPO are the bone marrow cells.
What are the main actions of EPO?
EPO stimulates the production of red blood cells (erythrocytes) in the bone marrow.
Where is Thyroid-Stimulating Hormone (TSH) produced and secreted?
TSH is produced and secreted by the anterior pituitary gland.
What is the stimulus for TSH secretion?
The stimulus for TSH secretion is Thyrotropin-releasing hormone (TRH) from the hypothalamus.
What are the target organs or cells of TSH?
The target organ of TSH is the thyroid gland.
What are the main actions of TSH?
TSH stimulates the thyroid gland to secrete thyroid hormones T3 (triiodothyronine) and T4 (thyroxine).
Where in the body is EPO produced?
EPO is produced in the kidneys.
What is the role of the Hypothalamic-Pituitary-Adrenal (HPA) axis in cortisol regulation?
The HPA axis involves the hypothalamus secreting CRH, which stimulates ACTH release from the anterior pituitary, leading to cortisol secretion from the adrenal cortex.
How does cortisol affect muscle tissue?
Cortisol stimulates the breakdown of muscle proteins into amino acids.
What is the role of aldosterone in potassium regulation?
Aldosterone increases the secretion of potassium from the blood into the urine.
What is the effect of aldosterone on sodium levels?
Aldosterone increases sodium reabsorption from the urine into the blood.
How do adrenaline and noradrenaline affect the bronchioles?
They cause bronchioles to dilate, increasing respiratory airflow.
What is the effect of adrenaline and noradrenaline on digestive functions?
They decrease digestive functions.
How does insulin affect liver glucose production?
Insulin inhibits the liver’s production of glucose from amino acids and glycerol (gluconeogenesis).
What is one additional action of insulin beyond glucose regulation?
Insulin stimulates body cells to utilize glucose for ATP production (glycolysis).
How does glucagon influence liver glycogen?
Glucagon stimulates the liver to break down stored glycogen to glucose (glycogenolysis).
What effect does glucagon have on fatty acids?
Glucagon stimulates the breakdown of fats to fatty acids in adipose tissue.
What is one action of oestrogen on the bones?
Oestrogen promotes the feminisation of the skeleton, including the widening of the hips.
How does oestrogen affect adipose tissue?
Oestrogen increases fat storage in adipose tissue.
What effect does oestrogen have on the reproductive organs?
Oestrogen promotes the growth and maturation of female reproductive organs, such as the vagina, uterus, and uterine tubes.
What role does progesterone play in pregnancy?
Progesterone prepares the uterus for pregnancy and helps maintain the pregnancy.
How does testosterone affect muscle tissue?
Testosterone increases muscle mass and strength.
What is one effect of testosterone on hair follicles?
Testosterone stimulates the growth of body hair, such as facial and pubic hair.
How does the endocrine system maintain homeostasis?
A) By using the nervous system to directly control all organs
B) By secreting hormones that regulate physiological processes
C) By increasing the speed of nerve impulses
D) By directly altering the DNA in cells
B) By secreting hormones that regulate physiological processes
Which of the following best describes the role of hormones in homeostasis?
A) Hormones always have an immediate effect on the body
B) Hormones bind to receptors and alter the function of target cells
C) Hormones directly alter the structure of organs
D) Hormones only work during emergencies
B) Hormones bind to receptors and alter the function of target cells
What is a common method by which the endocrine system maintains blood glucose levels?
A) Increasing water absorption in the intestines
B) Adjusting hormone levels such as insulin and glucagon
C) Directly affecting kidney filtration rates
D) Stimulating the release of digestive enzymes
B) Adjusting hormone levels such as insulin and glucagon
Which of the following is an example of a negative feedback mechanism in the endocrine system?
A) The release of adrenaline during stress
B) The increase of blood calcium levels to stimulate calcitonin release
C) The increase in thyroid hormone levels leading to decreased TSH secretion
D) The increase in blood glucose levels to stimulate insulin release
C) The increase in thyroid hormone levels leading to decreased TSH secretion
Which of the following is a chemical classification of hormones?
A) Carbohydrates and lipids
B) Proteins and steroids
C) Amino acids and nucleic acids
D) Enzymes and vitamins
B) Proteins and steroids
How are peptide hormones typically stimulated to be secreted?
A) By direct nerve impulses
B) By changes in blood levels of ions or nutrients
C) By other hormones
D) By temperature changes
C) By other hormones
What is a common mechanism by which hormones alter target cell activity?
A) Directly changing the cell membrane structure
B) Binding to specific receptors to activate or inhibit cellular processes
C) Altering the DNA sequence within the cell nucleus
D) Increasing the cell’s temperature
B) Binding to specific receptors to activate or inhibit cellular processes
Which type of hormone typically has a long-lasting effect due to its binding to intracellular receptors?
A) Peptide hormones
B) Steroid hormones
C) Amino acid-derived hormones
D) Protein hormones
B) Steroid hormones
What is the primary stimulus for endocrine gland secretion?
A) Environmental factors
B) Neural impulses
C) Blood levels of ions or nutrients, and other hormones
D) External temperatures
C) Blood levels of ions or nutrients, and other hormones
Which endocrine gland is often controlled by the hypothalamus through releasing and inhibiting hormones?
A) Thyroid gland
B) Adrenal gland
C) Pituitary gland
D) Pancreas
C) Pituitary gland
How do hormones from the hypothalamus reach the anterior pituitary gland?
A) Through direct neural connection
B) Via the hypophyseal portal system
C) Through the bloodstream
D) By diffusion through the cerebrospinal fluid
B) Via the hypophyseal portal system
Which of the following hormones travels through the hypophyseal portal system?
A) ADH (Antidiuretic Hormone)
B) TSH (Thyroid-Stimulating Hormone)
C) ACTH (Adrenocorticotropic Hormone)
D) CRH (Corticotropin-Releasing Hormone)
D) CRH (Corticotropin-Releasing Hormone)
How do hormones from the hypothalamus reach the posterior pituitary gland?
A) Through the hypophyseal portal system
B) Via direct neural connection
C) By entering the general bloodstream
D) By traveling through lymphatic vessels
B) Via direct neural connection
Which hypothalamic hormones are stored in the posterior pituitary gland?
A) ACTH and TSH
B) FSH and LH
C) ADH and Oxytocin
D) CRH and GnRH
C) ADH and Oxytocin
Where is erythropoietin (EPO) produced and secreted?
A) Adrenal glands
B) Kidneys
C) Thyroid gland
D) Pituitary gland
B) Kidneys
What stimulates the secretion of erythropoietin (EPO)?
A) Low blood calcium levels
B) High blood glucose levels
C) Low blood oxygen levels
D) High blood pressure
C) Low blood oxygen levels
What is the main action of erythropoietin (EPO)?
A) Regulate blood pressure
B) Stimulate red blood cell production
C) Regulate blood glucose levels
D) Increase white blood cell production
B) Stimulate red blood cell production
Where is cortisol produced and secreted?
A) Adrenal medulla
B) Adrenal cortex
C) Anterior pituitary gland
D) Thyroid gland
B) Adrenal cortex
What is the primary stimulus for cortisol secretion?
A) High blood glucose levels
B) Low blood potassium levels
C) ACTH from the anterior pituitary gland
D) Increased physical activity
C) ACTH from the anterior pituitary gland
What is a main action of cortisol?
A) Increase bone density
B) Stimulate glycogen storage in the liver
C) Increase blood glucose levels
D) Promote red blood cell production
C) Increase blood glucose levels
Where is aldosterone produced and secreted?
A) Adrenal medulla
B) Adrenal cortex
C) Pancreas
D) Thyroid gland
B) Adrenal cortex
What stimulates the secretion of aldosterone?
A) High blood glucose levels
B) Low blood pressure and high blood potassium levels
C) Low blood calcium levels
D) High blood oxygen levels
B) Low blood pressure and high blood potassium levels
What is the main action of aldosterone?
A) Increase glucose metabolism
B) Increase sodium reabsorption and potassium excretion
C) Decrease heart rate
D) Stimulate immune responses
B) Increase sodium reabsorption and potassium excretion
Where are adrenaline and noradrenaline produced and secreted?
A) Adrenal cortex
B) Adrenal medulla
C) Thyroid gland
D) Pancreas
B) Adrenal medulla
What stimulates the secretion of adrenaline and noradrenaline?
A) Increased blood glucose levels
B) Low blood calcium levels
C) Sympathetic nervous system activation
D) Increased blood oxygen levels
C) Sympathetic nervous system activation
What is a main action of adrenaline and noradrenaline?
A) Decrease heart rate
B) Promote digestion
C) Enhance the fight-or-flight response
D) Stimulate red blood cell production
C) Enhance the fight-or-flight response
Where is insulin produced and secreted?
A) Adrenal glands
B) Pancreas
C) Thyroid gland
D) Kidneys
B) Pancreas
What stimulates the secretion of insulin?
A) High blood glucose levels
B) Low blood calcium levels
C) High blood sodium levels
D) Low blood oxygen levels
A) High blood glucose levels
What is the main action of insulin?
A) Increase blood glucose levels
B) Stimulate glucose uptake by cells
C) Increase fat breakdown
D) Promote red blood cell production
B) Stimulate glucose uptake by cells
Where is testosterone produced and secreted?
A) Adrenal cortex
B) Testes
C) Thyroid gland
D) Pancreas
B) Testes
Give an example of a hormone secreted in response to a neural stimuli
Adrenaline (Epinephrine) and Noradrenaline (Norepinephrine): Produced by the adrenal medulla in response to sympathetic nervous system activation.
Give an example of a hormone secreted in response to a hormonal stimuli
Thyroid hormones stimulated by TSH
Cortisol stimulated by ACTH
Oestrogen stimulated by LH and FSH
Progesterone stimulated by LH
Testosterone stimulated by LH
Give an example of a hormone secreted in response to a humoral stimuli
Insulin: Secreted by the pancreas in response to high blood glucose levels.
Glucagon: Secreted by the pancreas in response to low blood glucose levels.
Aldosterone: Secreted by the adrenal cortex in response to high blood potassium levels and low blood pressure.
Erythropoietin (EPO): Secreted by the kidneys in response to low blood oxygen levels.
Calcitonin: Produced by the thyroid gland in response to high blood calcium levels.
Parathyroid Hormone (PTH): Secreted by the parathyroid glands in response to low blood calcium levels.
What hormone is secreted in response to high blood glucose levels?
Insulin
Which hormone is released when blood calcium levels are low?
Parathyroid Hormone (PTH)
What hormone is secreted by the adrenal medulla in response to sympathetic nervous system activation?
Adrenaline (Epinephrine) and Noradrenaline (Norepinephrine)
Which hormone is secreted by the kidneys in response to low blood oxygen levels?
Erythropoietin (EPO)
What hormone is released when blood potassium levels are high?
Aldosterone
Which hormone is secreted in response to a decrease in blood pressure and blood volume?
Aldosterone
What hormone is released from the anterior pituitary gland when the hypothalamus secretes CRH?
Adrenocorticotropic Hormone (ACTH)
Which hormone is secreted by the pancreas when blood glucose levels drop below the normal range?
Glucagon
What hormone is produced by the thyroid gland in response to high levels of thyroid-stimulating hormone (TSH)?
Thyroid Hormones (T3 and T4)
Which hormone is released by the anterior pituitary to stimulate the production of estrogen and progesterone in females?
Luteinizing Hormone (LH)
What hormone is secreted by the ovaries in response to stimulation by FSH and LH?
Estrogen
Which hormone is released by the adrenal cortex in response to ACTH from the anterior pituitary?
Cortisol
What hormone is secreted when the body needs to increase blood glucose levels, such as between meals or during fasting?
Glucagon
What hormone is secreted by the ovaries to prepare the uterus for pregnancy?
Progesterone
Which hormone is released in response to increased blood calcium levels?
Calcitonin
What hormone is secreted by the testes in response to LH from the anterior pituitary?
Testosterone
There are two main classes of hormones – what are they?
Steroid (lipid-soluble) hormones:
made of cholesterol
diffuse across plasma membrane to bind to intracellular receptors
Amino acid-based (lipid-insoluble) hormones:
can be amino acids, peptides or proteins
bind to plasma membrane receptors
How do hormones alter target cell activity?
stimulating protein synthesis
e.g. enzymes, structural proteins required for growth and cell division
activating enzymes
e.g. enzymes required for cell metabolism
altering membrane permeability
e.g. to water or ions
stimulating cell secretion
e.g. hormone secretion
stimulating cell division
body growth and development, production of RBC
When blood calcium levels increase above the normal range, _______________ will be secreted by the _______________ gland. When blood calcium levels decrease below the normal range, ________ will be secreted by the _______________ glands
When blood calcium levels increase above the normal range, calcitonin will be secreted by the thyroid gland. When blood calcium levels decrease below the normal range, PTH will be secreted by the Parathyroid glands
b. Two hormones that target the kidneys to maintain blood volume and, therefore, blood pressure are _______________ and _______________.
b. Two hormones that target the kidneys to maintain blood volume and, therefore, blood pressure are ADH and Aldosterone.
c. Insulin is produced and secreted by pancreatic _______________ cells, and glucagon is produced and secreted by pancreatic _______________ cells.
c. Insulin is produced and secreted by pancreatic beta cells, and glucagon is produced and secreted by pancreatic alpha cells.
d. The two hormones produced by the hypothalamus and secreted by the posterior pituitary are _______ and ___________________. These two hormones travel from the hypothalamus to the posterior pituitary via the ________________________________________.
d. The two hormones produced by the hypothalamus and secreted by the posterior pituitary are ADH and oxytocin. These two hormones travel from the hypothalamus to the posterior pituitary via the hypothalamic-hypophyseal tract.
e. The adrenal glands produce and secrete several different hormones. The adrenal cortex produces and secretes _________________ and __________________, whilst the adrenal medulla produces and secretes _______________________ and __________________________.
e. The adrenal glands produce and secrete several different hormones. The adrenal cortex produces and secretes Aldosterone and Cortisol, whilst the adrenal medulla produces and secretes Adrenaline and Noradrenaline.
f. The hormone that prepares the uterus for pregnancy is _______________.
f. The hormone that prepares the uterus for pregnancy is progesterone.
g. Amino acid-based hormones bind to _________________________ receptors, whilst steroid- based hormones bind to_______________ receptors.
g. Amino acid-based hormones bind to plasma membrane receptors, whilst steroid- based hormones bind to intracellular receptors.
h. Gonadotropin-releasing hormone (GnRH) is produced by the hypothalamus and travels to the anterior pituitary via the _________________________________________. GnRH stimulates the anterior pituitary to secrete __________ and __________.
h. Gonadotropin-releasing hormone (GnRH) is produced by the hypothalamus and travels to the anterior pituitary via the hypophyseal portal system. GnRH stimulates the anterior pituitary to secrete LH and FSH.
i. The hormone secreted in response to low blood oxygen levels is _________________________.
i. The hormone secreted in response to low blood oxygen levels is EPO.
j. _______________ promotes the growth of male reproductive organs and stimulates the production of sperm, whilst ____________ promotes the growth of female reproductive organs.
j. Testosterone promotes the growth of male reproductive organs and stimulates the production of sperm, whilst Oestrogen promotes the growth of female reproductive organs.
Identify the incorrect words in the following sentence, and state the correct words:
*ADH is secreted by the posterior pituitary in response to an increase in blood Ca+ levels. Changes in blood ion levels are an example of a hormonal stimulus. *
Incorrect: Ca2+, hormonal
ADH is secreted in response to an increase in blood Na+ levels. Changes in blood ions levels is an example of a humoral stimulus
Identify the incorrect words in the following sentence, and state the correct words:
Cortisol stimulates the hypothalamus to produce glucose from amino acids and glycerol. This process is known as glycogenolysis.
Incorrect: Hypothalamus, glycogenolysis
Cortisol targets the liver to produce glucose from amino acids and glycerol. This process is known as gluconeogenesis
- A patient presents with polyuria and polydipsia. You immediately suspect diabetes mellitus and test her blood glucose levels. They are found to be normal. What other condition do you think the patient could be suffering from, and what hormone does this involve?
Diabetes insipidus, hyposecretion of ADH
- A patient presents with hypokalaemia (low blood K+ levels), and you suspect an endocrine disorder involving the hypersecretion of a hormone.
a. Identify the hormone and endocrine gland most likely involved.
Aldosterone and adrenal cortex
- A patient presents with hypokalaemia (low blood K+ levels), and you suspect an endocrine disorder involving the hypersecretion of the hormone aldosterone.
b. State what effect this endocrine disorder may have on the patient’s blood pressure.
As aldosterone stimulates the kidney to return Na+ and, therefore, H2O to the blood, the hypersecretion of aldosterone can ↑ BV above normal levels, resulting in hypertension (higher than normal blood pressure).
