Related Concept Videos

Muscles of the Pelvic Floor and Perineum01:26

Muscles of the Pelvic Floor and Perineum

The muscles of the pelvic floor and perineum are crucial for supporting the pelvic organs, controlling continence, and aiding in sexual function, childbirth, and core stability. They are typically divided into the superficial perineal layer and the deep pelvic floor layer.
Perineal Layer
The perineum is a diamond-shaped area below the pelvic diaphragm, divided into an anterior urogenital triangle that contains the external genitals and a posterior anal triangle housing the anus. The urogenital...
Gonadal and Placental Hormones01:24

Gonadal and Placental Hormones

The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes of sexual development and reproduction.
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
Major Hormones and Their Functions01:27

Major Hormones and Their Functions

Hormones, the biochemical messengers produced by endocrine glands, are pivotal in regulating bodily functions and maintaining homeostasis. Each hormone's balance is crucial; imbalances can lead to significant physiological disruptions. Major hormones include oxytocin, cortisol, epinephrine, estrogen, testosterone, thyroxine, growth hormone, insulin, and glucagon.
Oxytocin, produced in the hypothalamus and released by the pituitary gland, plays a role in social bonding, childbirth, and lactation.
Physiology of the Genitourinary System III: Urine Concentration and Dilution01:20

Physiology of the Genitourinary System III: Urine Concentration and Dilution

The kidneys concentrate or dilute urine to maintain water and electrolyte balance. Nephrons, particularly the loop of Henle, play a crucial role in this process through the countercurrent multiplication system. This system establishes a high osmolarity in the renal medulla, which is essential for water reabsorption. In the loop of Henle’s descending limb, water is reabsorbed into the surrounding medulla due to its permeability to water. In contrast, the ascending limb actively transports...
Hormonal Control of the Ovarian Cycle01:30

Hormonal Control of the Ovarian Cycle

The ovarian cycle is meticulously regulated by the hypothalamic-pituitary-gonadal axis. This cycle orchestrates the release of a mature oocyte, essential for reproduction.
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle.  At puberty, GnRH secretion increases in both frequency and...
Hormonal Regulation01:40

Hormonal Regulation

Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.