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.

Cardiovascular System

Cardiovascular System:-

The cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of blood that the blood vessels transport. Responsible for transporting oxygen, nutrients, hormones, and cellular waste products throughout the body, the cardiovascular system is powered by the body’s hardest-working organ of the heart, which is only about the size of a closed fist. Even at rest, the average heart easily pumps over 5 liters of blood throughout the body every minute...


                            

The Heart

The heart is a muscular pumping organ located medial to the lungs along the body’s midline in the thoracic region. The bottom tip of the heart, known as its apex, is turned to the left, so that about 2/3 of the heart is located on the body’s left side with the other 1/3 on right. The top of the heart, known as the heart’s base, connects to the great blood vessels of the body: the aorta, vena cava, pulmonary trunk, and pulmonary veins. 

Cardiac Cycle:-

One heartbeat makes up one cardiac cycle.The top chamber of the heart is called atria.The bottom chamber of the heart called ventricles.Here are the actions that occur:

• Right atrium contracts < tricuspid valve opens < blood flows into the right ventricle.
• Left atrium contracts < bicuspid valve opens < blood flows into the left ventricle.
• Right ventricle contracts < tricuspid valve closes, pulmonary semilunar valve opens < blood is pushed into the trunk of the pulmonary artery.
• Left ventricle contracts < bicuspid valve closes, aortic semilunar valve opens < blood is pushed into the aorta.

Circulatory Loops

There are 2 primary circulatory loops in the human body: the pulmonary circulation loop and the systemic circulation loop.

Pulmonary circulation transports deoxygenated blood from the right side of the heart to the lungs, where the blood picks up oxygen and returns to the left side of the heart. The pumping chambers of the heart that support the pulmonary circulation loop are the right atrium and right ventricle.

Systemic circulation carries highly oxygenated blood from the left side of the heart to all of the tissues of the body (with the exception of the heart and lungs). Systemic circulation removes wastes from body tissues and returns deoxygenated blood to the right side of the heart. The left atrium and left ventricle of the heart are the pumping chambers for the systemic circulation loop.

Blood vessels 

Blood vessels are the body’s highways that allow blood to flow quickly and efficiently from the heart to every region of the body and back again. The size of blood vessels corresponds with the amount of blood that passes through the vessel. All blood vessels contain a hollow area called the lumen through which blood is able to flow. Around the lumen is the wall of the vessel, which may be thin in the case of capillaries or very thick in the case of arteries.

There are three major types of blood vessels: arteries, capillaries and veins

Arteries and Arterioles: 

Arteries are blood vessels that carry blood away from the heart. Blood carried by arteries is usually highly oxygenated, having just left the lungs on its way to the body’s tissues. The pulmonary trunk and arteries of the pulmonary circulation loop provide an exception to this rule – these arteries carry deoxygenated blood from the heart to the lungs to be oxygenated.small branches of arteries are called arterioles.

Capillaries: 

Capillaries are the smallest and thinnest of the blood vessels in the body and also the most common. They can be found running throughout almost every tissue of the body and border the edges of the body’s avascular tissues. Capillaries connect to arterioles on one end and venules on the other.

Veins and Venules: 

Veins are the large return vessels of the body and act as the blood return counterparts of arteries. Because the arteries, arterioles, and capillaries absorb most of the force of the heart’s contractions, veins and venules are subjected to very low blood pressures. This lack of pressure allows the walls of veins to be much thinner, less elastic, and less muscular than the walls of arteries.

Blood
The average human body contains about 4 to 5 liters of blood. As a liquid connective tissue, it transports many substances through the body and helps to maintain homeostasis of nutrients, wastes, and gases. Blood is made up of red blood cells, white blood cells, platelets, and liquid plasma.

                            
• Red Blood Cells: Red blood cells, also known as erythrocytes, are by far the most common type of blood cell and make up about 45% of blood volume. 

• White Blood Cells: White blood cells, also known as leukocytes, make up a very small percentage of the total number of cells in the bloodstream, but have important functions in the body’s immune system. 

• Platelets : Also known as thrombocytes, platelets are small cell fragments responsible for the clotting of blood and the formation of scabs. Platelets form in the red bone marrow from large megakaryocytic cells that periodically rupture and release thousands of pieces of membrane that become the platelets. Platelets do not contain a nucleus and only survive in the body for up to a week before macrophages capture and digest them.

• Plasma: Plasma is the non-cellular or liquid portion of the blood that makes up about 55% of the blood’s volume. Plasma is a mixture of water, proteins, and dissolved substances. Around 90% of plasma is made of water, although the exact percentage varies depending upon the hydration levels of the individual. 

Functions of the Cardiovascular System:-

The cardiovascular system has three major functions: transportation of materials, protection from pathogens, and regulation of the body’s homeostasis.

• Transportation: The cardiovascular system transports blood to almost all of the body’s tissues. The blood delivers essential nutrients and oxygen and removes wastes and carbon dioxide to be processed or removed from the body. Hormones are transported throughout the body via the blood’s liquid plasma.

• Protection: The cardiovascular system protects the body through its white blood cells. White blood cells clean up cellular debris and fight pathogens that have entered the body. Platelets and red blood cells form scabs to seal wounds and prevent pathogens from entering the body and liquids from leaking out. Blood also carries antibodies that provide specific immunity to pathogens that the body has previously been exposed to or has been vaccinated against.

• Regulation: The cardiovascular system is instrumental in the body’s ability to maintain homeostatic control of several internal conditions. Blood vessels help maintain a stable body temperature by controlling the blood flow to the surface of the skin. Blood vessels near the skin’s surface open during times of overheating to allow hot blood to dump its heat into the body’s surroundings. 

The Circulatory Pump 

The heart is a four-chambered “double pump,” where each side (left and right) operates as a separate pump. The left and right sides of the heart are separated by a muscular wall of tissue known as the septum of the heart. 

The right side of the heart receives deoxygenated blood from the systemic veins and pumps it to the lungs for oxygenation. 

The left side of the heart receives oxygenated blood from the lungs and pumps it through the systemic arteries to the tissues of the body. Each heartbeat results in the simultaneous pumping of both sides of the heart, making the heart a very efficient pump.

Blood Pressure 

Several functions of the cardiovascular system can control blood pressure. Certain hormones along with autonomic nerve signals from the brain affect the rate and strength of heart contractions. Greater contractile force and heart rate lead to an increase in blood pressure. Blood vessels can also affect blood pressure. 

Vasoconstriction decreases the diameter of an artery by contracting the smooth muscle in the arterial wall. The sympathetic (fight or flight) division of the autonomic nervous system causes vasoconstriction, which leads to increases in blood pressure and decreases in blood flow in the constricted region. 

Vasodilation is the expansion of an artery as the smooth muscle in the arterial wall relaxes after the fight-or-flight response wears off or under the effect of certain hormones or chemicals in the blood. The volume of blood in the body also affects blood pressure. A higher volume of blood in the body raises blood pressure by increasing the amount of blood pumped by each heartbeat. Thicker, more viscous blood from clotting disorders can also raise blood pressure.

Heart Sounds:-

During one cardiac cycle, you can hear two heart sounds. The sounds are called Lubb and Dubb. 

                                   
Lubb:-  This is the first heart sound and occurs when the ventricles contract and the tricuspid and bicuspid valves snap shut.

Dubb:- This is the second heart sound and occurs when the atria contract and the pulmonary and aortic semilunar valves snap shut.

Cardiac Conduction System

The cardiac conduction system consists of a group of structures that send electrical impulses through the heart. when cardiac muscle receive an electrical impulse , it contracts.

Components of the cardiac conduction system:-

• Sinoatrial Node (SA node)
• Atrioventricular Node (AV node)
• Bundle of His
• Purkinje Fibers

                                             

Electrocardiogram (ECG or EKG)

This is the test used by physician to know if the cardiac conduction system is working properly. The first wave P indicates that an electrical impulse was sent through the atria, causing them to contract (Depolarization).

                                      

The O, R, and S waves occurs together and make up the ORS complex. This complex indicates that an electrical impulse was sent through the ventricles, causing them to contract(Depolarization).

Finally, T wave indicates electrical changes that occurs in the ventricles as they relax (Repolarization).

Why I Choose This System?

•  It takes 20 seconds for blood to circulate the entire body. Oxygenated blood leaves the aorta about about 1 mile an hour.

• The power output of the heart ranges from 1-5 watts per minute. Which is the equivalent to the usage of a 60 watt bulb. It has been said that enough energy is produced a day to drive a truck 20 miles. 

• “Ventricle” means “little belly” in Latin where as “Atrium” is Latin for “entrance hall”.

• Red blood cells live for upto 4 months and make approximately 250,000 round trips around the body before returning to the bone marrow, where they were born, to die. Between 2.5 and 3 million red blood cells (erythrocytes) are lost and replaced every second.

• Human blood is colorless, it is the hemoglobin that makes it red. 

• Due to the heart having its own electrical impulse, it will continue to beat even when removed from the body as long as it has an adequate supply of oxygen.

• Though weighing only 11 ounces on average, a healthy heart pumps 2,000 gallons of blood through 60,000 miles of blood vessels each day.

• The fetal heart rate is approximately twice as fast as an adult’s, at about 150 beats per minute. By the time a fetus is 12 weeks old, its heart pumps an amazing 60 pints of blood a day.

• Five percent of blood supplies the heart, 15-20% goes to the brain and central nervous system, and 22% goes to the kidneys.

• A woman’s heart typically beats faster than a man’s. The heart of an average man beats approximately 70 times a minute, whereas the average woman has a heart rate of 78 beats per minute.

Personal summary and Goals

I am Ramanjit Kaur, 29 year of age, having two beautiful girls.I am living in Rock Hill, South Carolina. Traveling is one of my hobbies. I like watching movies and TV series and cooking. I am currently following Being Mary Jane on Netflix, a very fascinating series. When I am passionate about something, I go to extreme efforts to meet my passion. I love to go out and explore the world.

I would describe myself as a well presented, hard working person who thrives at the chance of learning new skills. I have a mature outlook , excellent communication skills and enjoy working with the public. I always like to get the task I have been given done in a professional and efficient manner and I have proved these skill through my studies at college and work placements. I like to think I am someone who works well alongside others and east to get along with as I am a sociable person. My work placements have helped me build my confidence as a person and hopefully will carry on so. I am also willing to take on any training necessary to enable me to carry out my work well.

I pay great attention to detail in my work and enjoy researching and developing new products and testing them to be used and improving the process. I think in a logical way and I am able to work well in a team environment working together to ensure that we reach the same end goal.

I am honest and trustworthy. I am very dedicated to my career choice and to that of an employer. I am able to problem solve well.I am multitasking and trilingual (English, Hindi, Punjabi).

I would like to do RN in my future. I like to take more responsibility and get more education. I want to be a successful women in my life. My goal is to commit myself to lifelong learning. I strongly believe that education does not end. Part of being a nurse is the application of knowledge and the continuation of learning. This allows me a chance to interact with various people from different backgrounds and provides me with assurance to why I do what I do.

Conclusively, choosing medical field as a career was a result of my past experience. One of my most important goals is to community service to those in need of medical assistance.