Introduction and Pituitary gland

The given following stimuli which are responsible for the respond of release of hormones from endocrine gland, they are given as follows:

1. Hormones from other endocrine glands.
2. Chemical characteristics of the blood.
3. Neural stimulation.

The production of most of the hormones is managed by the negative feedback system. The nervous system and certain endocrine tissues monitor the different types of internal conditions of the body. When the action is required to for homeostasis maintenance, hormones are released, either directly by an endocrine gland or indirectly through the action of the hypothalamus of the brain, other endocrine glands release hormones when they are stimulated. The hormones activate the target cell, the initiation of physiological changes adjust the body condition. When normal conditions have been recovered, the corrective action – the discontinuous production of hormones. Thus, the original or unwanted condition has been repaired, or negated, corrective actions decrease in negative feedback. For example, the amount of glucose in the blood is maintained by negative feedback which controls the secretion of insulin and glucagons.

The production of some hormones is controlled by the positive feedback. In the system of this, hormones cause a condition to escalate, rather than decrease. That condition intensifies the increase meant of production of hormones. The type of positive feedback is uncommon, but during childbirth it occurs, where hormone levels build with increasingly intense labor contractions which is much ,more similar to the lactation, in response to nursing the hormones levels increased, by which the milk production is increased. The hypothalamus produces the hormones produce a hormone which causes the milk let down and uterine contraction is oxytocin.

Endocrine Glands

Pituitary gland

The pituitary gland is joined by a slender stalk at the bottom of the hypothalamus that is generally called the infundibulum. The lower region of the diencephalons is made by the hypothalamus and which lies just above the brain stem. The anterior pituitary gland such as anterior lobe or adenohypophysis and the posterior pituitary gland such as posterior lobe or neurohypophysis these are the two major kinds of regions consists by these glands. The hypothalamus controls the glandular secretion of the pituitary gland.

The hypothalamus controls the different types of internal body conditions. Which receives nervous stimuli from receptors throughout the body and the chemical and physical characteristics of the blood, including temperature, blood pressure, and nutrient, hormone, and water content are monitored. The hypothalamus stimulates the cellular activity in various parts of the body when certain developmental changes are required. The production of hormones is directed by the anterior and posterior pituitary glands. These glands communicate with directives by the hypothalamus by using one of the following two pathways.

The Pituitary gland is found at the inferior part of the brain and that is joined by the Pituitary Stalk. It is the functional place for an endocrine system where everything happens within the gland so that this gland is commonly called master gland. It is also divided into two sections: the anterior lobe and the posterior lobe. The transformation of hormones involved in the Posterior pituitary that control all other hormones of the body of human beings.

Posterior pituitary

The hypothalamus and the posterior pituitary communicated by the neurosecretory cells that cross or traverse the short distance between the hypothalamus and the posterior pituitary. The hormones are produced by the cell bodies of the neurosecretory cells and which are stored in vesicles and transformed through the axon and stored in the axon terminals which lie in the posterior pituitary. When the neurosecretory cells are stimulated, the action potential produced triggers the production of the stored hormones from the axon terminals to a capillary network within the posterior pituitary. There are two hormones oxytocin and antidiuretic hormone (ADH) which are produced and released. One of them is not able to produce ADH which can cause Diabetes Insipidus that means the loss of ions from the blood is the result of a person is producing large amounts of urine.

The posterior lobe is the most important component for the composing the neural tissue and which is derived from the hypothalamus. The storage of oxytocin and the Antidieuretic hormone is the main function of this. Into The capillaries of the lobe is released by the hormones when hypothalamic neurons fire.

Anterior pituitary

With the help of chemicals such as releasing hormones and inhibiting hormones, information interchange occurs in between the hypothalamus and the anterior pituitary that are produced by the hypothalamus and then delivered to the anterior pituitary through blood vessels. The neurosecretory cells produce the releasing and inhibiting hormones by the aid of specialized neurons of the hypothalamus. The hormones are thus passed into a capillary network or primary plexus, and transported from veins or hypophyseal portal veins, into a second capillary network or secondary plexus that supplies the anterior pituitary. Those hormones then diffuse from the secondary plexus into the anterior pituitary, where they start the production of specific hormones by the anterior pituitary. Most of the hormones are tropic hormones or tropics that are produced by the anterior pituitary. These hormones are the hormones which stimulate other endocrine glands to secrete their hormones.

The oral ectoderm produced from the anterior lobe is composed of glandular. From a network of capillaries epithelium, it communicates with the hypothalamus.

Releasing hormones are released by the anterior pituitary lobe from the hypothalamus via a portal vein system called the hypothalamic-hypophyseal portal system.

References

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