The Endocrine System

Introduction:-

The word endocrine derives from the Greek words "endo," meaning within, and "crine," meaning to secrete, 

The endocrine system is the collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things.

The endocrine system is made up of:-

• The Hypothalamus
• The pituitary gland
• Thyroid gland
• Parathyroid glands
• Adrenal glands
• Kidneys
• Pineal gland
• Pancreas
• Ovaries (in females)
• Testicles (in males) 

Types Of Hormone:

• Steroidal Hormone
• Nonsteroidal Hormone
• Prostaglandins Hormone

Hormone Production:

• The Hypothalamus is located in the diencephalon of the brain and produces the hormones oxytocin and antidiuretic hormone(ADH). These hormones are transported to the posterior pituitary, where they are stored and released as directed by the hypothalamus.

• The Pituitary Gland also known as "hypophysis" is located at the base of the brain and controlled by the hypothalamus.

          Pituitary is divided into two lobes: Anterior Lobe and Posterior Lobe

• The Thyroid Gland consists of two lobes and sits below the voice of box or larynx. Hormones secretes: Thyroid Hormones and Calcitonin.

• The Parathyroid Gland are small glands embedded into the posterior surface of the thyroid gland. Hormone secrets : Parathormone or parathyroid hormone(PTH).

• The Adrenal Glands sits on the top of each kidney. Divided into two portions: The adrenal medulla and the adrenal cortex.

• The Pancreas is located behind the stomach. it is endocrine as well as exocrine gland. 

• The Pineal Gland is a small gland located between the cerebral hemisphere. it secrets a hormone called Melatonin.

• The Thymus Gland lies between the lungs. it secrets a hormone called "Thymosin".

• The Gonads, the ovaries and testes are reproductive organs that secrets hormones. The ovaries release "Estrogen and Progesterone". The Testes produce "Testosterone".

The Stress Response:

Any stimulus that produces stress is termed a stressor. Prolonged stress cause the release of Cortisol. Cortisol slows down body repair because it prevents protein synthesis and inhibits immune responses, which is why a person under stress becomes more susceptible to illness.

Why I Choose This System:

• This System is related to our hormones secrets in the body. The glands are responsible to produce different kind of hormones.
• A gland is a group of cells that produces and secretes, or gives off, chemicals. 
• Endocrine glands, on the other hand, release more than 20 major hormones directly into the bloodstream where they can be transported to cells in other parts of the body.
• growth hormone, which stimulates the growth of bone and other body tissues and plays a role in the body's handling of nutrients and minerals

The Nervous System

Nervous System

The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts. The brain and spinal cord form the control center known as the central nervous system (CNS), where information is evaluated and decisions made. The sensory nerves and sense organs of the peripheral nervous system (PNS) monitor...

Functions of NS:-

• Sensory
• Integration
• Motor.   

Divisions of the Nervous System

Nervous Tissue:-
The majority of the nervous system is tissue made up of two classes of cells: neurons and neuroglia.

• Neurons. Neurons, also known as nerve cells, communicate within the body by transmitting electrochemical signals. Neurons look quite different from other cells in the body due to the many long cellular processes that extend from their central cell body.

                                       

• The cell body is the roughly round part of a neuron that contains the nucleus, mitochondria, and most of the cellular organelles. Small tree-like structures called dendrites extend from the cell body to pick up stimuli from the environment, other neurons, or sensory receptor cells. Long transmitting processes called axons extend from the cell body to send signals onward to other neurons or effector cells in the body. 
  
  There are 3 basic classes of neurons: 

1. Afferent neurons. 
2. Efferent neurons. 
3. Interneurons. 

• Neuroglia. Neuroglia, also known as glial cells, act as the “helper” cells of the nervous system. Each neuron in the body is surrounded by anywhere from 6 to 60 neuroglia that protect, feed, and insulate the neuron. 

Central Nervous System Consists:-

The brain:-

Brain is a soft, wrinkled organ that weighs about 3 pounds, is located inside the cranial cavity, where the bones of the skull surround and protect it. The approximately 100 billion neurons of the brain form the main control center of the body. The brain and spinal cord together form the central nervous system (CNS), where information is processed and responses originate. 

Spinal Cord:-

The spinal cord is a long, thin mass of bundled neurons that carries information through the vertebral cavity of the spine beginning at the medulla oblongata of the brain on its superior end and continuing inferiorly to the lumbar region of the spine.

Meninges
The meninges are the protective coverings of the central nervous system (CNS). They consist of three layers: 

• Dura mater
• Arachnoid mater
• Pia mater

Peripheral Nervous System Consists:-

• Cranial Nerves:- Consists 12 cranial nerve that originate from the brain.
• Spinal Nerves:- Consists 31 pairs of spinal nerve that originate from the spinal cord.

Why I  Choose This System?

These are the important parts of our Nervous system:-

Cerebellum:-

Part of the hindbrain in vertebrates. In humans it lies between the brainstem and the cerebrum, and plays an important role in sensory perception, motor output, balance, and posture.

cerebrum

In humans it is the largest part of the brain and is the seat of motor and sensory functions, as well as the higher mental functions such as consciousness, thought, reason, emotion, and memory.

spinal cord

A thick, whitish cord of nerve tissue that is a major part of the central nervous system. It extends from the brain stem through the spine, with nerves branching off to various parts of the body.

brain stem

The part of the brain that connects the spinal cord to the forebrain and cerebrum.