Hormones, Homeostasis & Reproduction (6.6)
Homeostasis and Feedback Mechanisms
Homeostasis = maintaining a stable internal environment. In effect, it is a balance beam in the body.
|
|
Insulin, GLucaGon & Diabetes
The pancreas responds to blood glucose levels by releasing one of two hormones, either insultin or glucagon, as needed. Blood glucose concentration is maintained at a set point of about 5mmol/L. When blood glucose rises (say after eatting) or falls (say after a workout), the homeostatic mechanisms are induced occur via the hormones insulin and glucagon to return the balance beam to normal.
Insulin and glucagon are produced by the pancreas. A single organ with two glands.
If blood glucose levels fall below 5mmol/L
Hormones are broken down/ degraded relatively quickly so that signals do not continue. Insulin is broken down by the cells it acts upon, therefore its secretion must be ongoing. Secretion begins minutes upon eating and may continue for several hours after a meal. Blood Glucose feedback system Insulin and Glucagon homeostasis |
Diabetes
Diabetes is consistent elevated blood glucose levels even after fasting. This can cause damage to the tissues (particularly proteins), causes impairment of water absorption in the kidney which increases the urine volume and increases dehydration. It also cases a constatn thirst and feelings of tired and cravings of sugary drinks.
There are two types of diabetes: Type 1 and Type 2 |
Type I: Early Onset Diabetes Type 1 is the inability to produce sufficient quantities of insulin.
Treatment:
|
Type II- Late onset diabete
Type 2 is the inability to process or respond to insulin due to either deficiency of insulin receptors or glucose transporters on target cells
Treatment:
|
Leptin & Obesity
Leptin acts on the hypothalamus of the brain to inhibit appetite. It is secreted by adipose tissue (fat storage cells) and the amount leptin released is controlled by the amount of food intake and amount of adipose tissue in the body.
Leptin and Body weight regulation |
https://www.erxpharmaceuticals.com/wp-content/uploads/2019/08/[email protected]
|
Obesity
|
The 1950s experiments on mice and their use of leptin, were then used to try and control obesity in humans through a double blind experiment carried out by biotech company Amgen.
|
Thyroxin & Hypothyroidism
Thyroxin (T4) is a hormone that regulates metabolic rate and controls body temperature, which is secreted by the thyroid gland.
|
Hypothyroidism
Melatonin & Jet LaG
|
Melatonin is a hormone secreted by the pineal gland which controls our circadian rhythms. Circadian rhythms the 24 hour cycle that includes your rhythms of behavior and sleep. These rhythums will continue even if a person is placed in continuous light or darkness due to internal system.
Our Circadiam Rhythm is dependent on two groups of cells in hypothalamus called the suprachiasmatic nuclei (SCN). These cells set a daily rhythm even if you have NO external cues about time of day. They control the release of melatonin in the body.
Jet Lag Jet Lag is the experience of someone who has crossed 3+ time zones during travel which casues difficulty remaining awake during daylight hours, difficulty sleeping through the night, fatigue, irritability, headaches, and indigestion. Usually, last for a few days untl the body's sleep cycle readjusts.
Caused by the SCN and pineal gland continuing to set your circadian rhythm to suit the time of day/night point from the point of departure rather than your destination. Melatonin: can be used to prevent Jet Lag. When taken orally when sleep should be occurring at the destination, it can aid in the resetting of the Carcadian rhythums. Most effective when traveling eastwards and crossing 5+ time zones. |
William Harvey and Sexual reproduction
William Harvey is a scientist who studied sexual reproduction using deer. He attempted to test Aristotle's "see and soil" theory.
|
Male, Female, & Sex Hormones
MalePresence of gene (SRY) on Y chromosome activates the DNA binding protein, TDF (testes determining factor).
|
FemaleAbsence of the SRY gene, leads to no TDF production. As a result, gonads develop as ovaries
|
5 major sex hormones:
Pituitary Hormones: Folicle Simulating Hormone (FSH) & Luteinizing Hormone (LH) Androgen Hormones (Produced by the ovaries and testies): Estrogen, Progesterone, & Testosterone. All 5 exist in both sexes. The differences lie in the amounts of each that are produced. |
Sex Hormones in Males
|
Sex Hormones in Females
|
Male and FemaLe Anatomy & Functions
Male Reproductive System |
Female Reproductive System |
The Menstral Cycle
The Menstrual cycle/ Ovarian Cycle occurs once a woman reaches puberty and until menopause. It does NOT occur during pregnancy. Each time a cycle occurs, pregnancy is possible.
|
As you walk through the stages, note that FSH and LH control the ovary development while Estrogen and Progesterone control the uterus. However, both sets are inhibitory of the other set, which creates a negative feedback loop making sure a woman does not get pregnant when the uterus lining is not ready.
|
|
|
In Vitro Fertilization (IVF)
Ethics of IVF:
Ethics of IVF - internet sicentific publications Pros:
|
In-vitro Fertilization (IVF) is the suspension of natural hormone cycles and artificial doses of hormones to induce superovulation and establish pregnancy.
Stages of IVF |
|
|