3020 Lecture 13
Amber Stokes・40 minutes read
Hormones come in three major classes - peptides and proteins, amino acid derivatives, and steroids, each with specific effects on various targets in the body, such as growth, reproduction, and stress responses. The pituitary gland, divided into anterior and posterior parts, releases hormones like ADH and oxytocin, regulating functions like urine production and uterine contractions, with oxytocin also influencing reproductive behavior and emotional connections.
Insights
- Hormones can be classified into three major classes: peptides and proteins, amino acid derivatives, and steroids, each with distinct functions and effects on the body's systems.
- The posterior pituitary gland receives neurohormones like ADH and oxytocin from the hypothalamus, with ADH regulating urine volume to retain water and oxytocin stimulating uterine contractions during childbirth, showcasing the gland's crucial role in maintaining fluid balance and reproductive functions.
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Recent questions
What are the three major classes of hormones?
Peptides and proteins, amino acid derivatives, and steroids.
How do hormones impact non-endocrine targets?
By activating receptors in structures like muscles, bones, and skin.
What are the two categories of hormones based on solubility?
Hydrophilic (water-soluble) and lipophilic (fat-soluble).
What are the functions of the anterior and posterior pituitary glands?
The anterior produces essential hormones, while the posterior receives neurohormones.
What are the roles of oxytocin in the body?
Stimulating milk ejection, uterine contractions, and reproductive behavior.
Related videos
Summary
00:00
"Overview of Hormone Classes and Functions"
- Three major classes of hormones: peptides and proteins, amino acid derivatives, and steroids.
- Peptides and proteins include glycoproteins, amino acid derivatives like catacholamines and melatonin, and will be discussed in detail.
- Steroids encompass sex hormones (estrogen, testosterone) and corticosteroids (stress hormones), to be elaborated on in the reproductive lecture.
- Hormones have direct effects on non-endocrine targets, activating receptors in structures like muscles, bones, and skin.
- Examples of hormones with direct effects include growth hormone and prolactin, impacting growth and various functions.
- Hormones with indirect effects activate receptors in other endocrine glands, stimulating or inhibiting hormone production.
- Examples of hormones with indirect effects include TSH, luteinizing hormone, and follicle stimulating hormone.
- Hormones are classified into hydrophilic (water-soluble) and lipophilic (fat-soluble) categories, impacting their movement and function.
- Lipophilic hormones, like steroids and thyroid hormones, require transport proteins to move through the bloodstream and bind to nuclear receptors.
- Hydrophilic hormones, unlike lipophilic ones, do not need transport proteins and bind to membrane receptors on cell surfaces to induce cellular responses.
25:49
"Pituitary Gland: Anterior and Posterior Functions"
- The pituitary gland is divided into anterior and posterior parts, with the anterior being glandular and the posterior being fibrous in structure.
- The anterior pituitary originates from an outpocketing of the roof of the mouth during development.
- The posterior pituitary originates from axons developing within the hypothalamus and moving through the stalk connecting the hypothalamus.
- The posterior pituitary receives neurohormones from the hypothalamus, including ADH and oxytocin.
- ADH targets kidney tubules to decrease urine production, while oxytocin targets mammary glands and uterine muscles.
- ADH, an antidiuretic hormone, decreases urine volume to retain water in the bloodstream, triggered by dehydration.
- Osmotic concentration increase in the blood signals the release of ADH from the hypothalamus to reduce urine volume.
- Decreased blood volume and pressure prompt the synthesis of ADH to increase vasoconstriction and raise blood pressure.
- Oxytocin, known as the "love hormone," stimulates milk ejection reflex in mammals and uterine contractions during childbirth.
- Oxytocin's actions can be triggered by the sucking action of young mammals or even hearing a baby cry, showcasing its diverse functions.
49:22
Oxytocin: Hormone of Childbirth and Bonding
- Oxytocin is released during childbirth when the baby's head pushes against the cervix, signaling the hypothalamus to release oxytocin into the bloodstream.
- Oxytocin stimulates uterine contractions until the pressure from the baby's head is relieved after birth.
- Oxytocin secretion continues post-childbirth, aiding in the return of the uterus to its normal size, especially in breastfeeding individuals.
- Oxytocin regulates reproductive behavior, promoting pair bonding and affectionate feelings, often referred to as the "cuddle hormone."
- Oxytocin also influences arousal and orgasm, playing a role in emotional connections and attachment.
- In non-mammals, a hormone called Arginine Vasotocin regulates functions similar to oxytocin, such as oviduct contractions in egg-bearing animals.
- The anterior pituitary gland, distinct from the posterior pituitary, produces essential hormones through the hypothalamus-hypophyseal portal system.
- The hypothalamus secretes releasing and inhibiting hormones that control the anterior pituitary's hormone production and secretion.
- Growth hormone from the anterior pituitary stimulates muscle, bone, and tissue growth, with excessive secretion leading to conditions like gigantism.
- Gigantism, caused by excessive growth hormone in children, can result in extreme height and health complications due to increased joint stress and caloric needs.
01:16:19
Lecture 13: Growth Hormone Overview
- Growth hormone discussed in lecture 13.
