Human organ systems The human body is composed of 11 organ systems. We have covered 7 in this course. - Circulatory - Immune - Respiratory - Digestive - Musculoskeletal - Nervous - Urinary - Endocrine - Reproductive - Integumentary - Lymphatic

THE ENDOCRINE SYSTEM

The endocrine system is made up of glands that produce and secrete hormones (chemical substances produced in the body that regulate the activity of cells or organs – “chemical messengers”). These hormones regulate the body's growth, metabolism, and sexual development and function. The hormones are released into the bloodstream and may affect one or several organs throughout the body (i.e. the difference between target and non-target hormones). Hormones transfer information from one set of cells to another to coordinate the functions of different parts of the body. The major glands of the endocrine system are the hypothalamus, pituitary, thyroid, parathyroids, adrenals, pineal, and the reproductive organs (ovaries and testes). The pancreas is also a part of this system; it has a role in hormone production as well as in digestion.

Major endocrine glands

Function of the Endocrine Glands Pituitary Gland: "master gland" because of its great influence on the other body organs. Its function is complex and important for overall well-being.

Function of the Endocrine Glands Hypothalamus: releases hormones that start and stop the release of pituitary hormones.

Function of the Endocrine Glands Thymus is a gland needed early in life for normal immune function. Secretes hormones which help develop the immune system.

Function of the Endocrine Glands Pineal Gland: produces melatonin, which controls sleep patterns.

Function of the Endocrine Glands Testes: only in males, produce the hormone testosterone. Testosterone helps a boy develop and then maintain his sexual traits.

Function of the Endocrine Glands Ovaries: only in females, produce estrogen and progesterone. These hormones are responsible for developing and maintaining female sexual traits, as well as maintaining a pregnancy.

Function of the Endocrine Glands Thyroid: secretes hormones that control metabolism.

Function of the Endocrine Glands Adrenal Glands: secretes hormones that help the body respond to stressors produces some sex hormones (for some secondary sex characteristics in both men and women).

Function of the Endocrine Glands Parathyroid Glands: make hormones that help control calcium and phosphorous levels in the body (important for bone growth).

Example Hormones Antidiurectic hormone (ADH) – from the Pituitary gland. Increases water absorption in the body (kidneys).

Example Hormones Oxytocin – from the Pituitary gland. Controls labour and milk production for nursing mothers.

Example Hormones Adrenaline – Produced in the adrenal glands. Adrenaline works with noradrenaline to produce the "fight or flight" response by increasing the supply of oxygen to the brain and muscles, dilating the pupils, and suppressing bodily functions not useful in an emergency situation (such as digestion).

Example Hormones Growth Hormone (GH) – from the pituitary gland. GH stimulates growth during childhood and also stimulates cell reproduction, which helps adults maintain muscle and bone mass.

LOCATION IMPORTANT HORMONE PITUITARY Growth hormone (body growth) PINEAL Melatonin (control sleep patterns) THYROID Thyroxin (control metabolism – how fast you burn fuel) ADRENAL Adrenaline (prepares body for stressful situations) PANCREAS Insulin (controls blood glucose levels) TESTES Testosterone (secondary sex traits, growth) OVARIES Estrogen, progesterone (sex traits, reproduction)

Endocrine disorders Diabetes – low levels of insulin Goiter – swelling of the neck caused by enlargement of the thyroid gland Hyperthyroidism – overactive thyroid gland; sweating, nervous behaviour, weight loss Gigantism – high levels of growth hormone Dwarfism – low levels of growth hormone Sleep disorders / anxiety / depression – low levels of melatonin

THE CIRCULATORY SYSTEM

The circulatory system transports gases and nutrients throughout the body and carries away wastes. The system is made up of blood, the heart, and blood vessels.

Function of The Circulatory System Moves oxygen from the lungs to all the body cells Moves carbon dioxide from the body cells to the lungs Moves nutrients from the small intestine to the body cells Moves waste materials from the body cells to the kidneys and skin to be removed

The Blood Did you know… - It takes about 20 seconds for a RBC to circulate the entire body Blood is a type of connective tissue that circulates through your body, it consists of 4 components: Red Blood Cells (RBC) White Blood Cells (WBC) Platelets Plasma RBC: hemoglobin allowing them to transport oxygen throught the body about 50% WBC: infection fighting cells 1% of volume -platelets help in blood clotting less than 1% Plasma protein rich liquid that carries the blood cells along (about 50%)

Components of Blood Platelets Plasma Red Blood Cells -make up approx. 45% of blood volume -contain hemoglobin (protein that carries O2) -have no nucleus (when mature) White Blood Cells -make up less than 1% of blood volume -function is to fight infection -have a nucleus Platelets -are actually just fragments of cells -function is to clot blood Plasma -liquid that suspends the other 3 components -makes up approx. 55% of blood volume -contains dissolved materials (i.e. protein)

Blood Vessels 1) Arteries: blood vessels that carry blood away from the heart heart pumps blood with force so arterial blood pressure is higher than venous blood pressure due to higher pressure, artery walls are thicker than those of veins 2) Veins: blood vessels that carry blood toward the heart contents are under low pressure so walls are thinner than those of arteries 3) Capillaries: tiny blood vessels with very thin walls to allow substances to diffuse between the blood and the body fluids and tissues are the blood vessels that link arteries and veins oxygen and nutrients diffuse from the blood into the surrounding tissues carbon dioxide and other wastes diffuse from tissues into the blood

The Heart (a pump): Made of 3 types of tissue: - Cardiac Muscle Tissue - Nerve Tissue - Connective Tissue Consists of four chambers: - 2 Atria (left and right atrium) - 2 Ventricles (left and right ventricles)

Let’s explore the flow through the heart…. (to body) (from body) (to lungs) (from lungs) (from body)

Circulatory System Diseases and Disorders Coronary artery disease Heart attack – blocked coronary vessel Heart murmurs Irregular heart beat Anemia – low hemoglobin or low iron Leukemia Hemophilia – inherited blood clotting disorder

THE RESPIRATORY SYSTEM

Review the following diagram to locate the system’s components: nasal cavity mouth pharynx larynx (vocal cords) trachea bronchi bronchioles alveoli lungs diaphragm

Air travels through the trachea to the lungs Air travels through the trachea to the lungs. The trachea contains many epithelial cells that have hairlike projections called cilia. Cilia help filter out and remove foreign materials (such as dust) that might otherwise enter the bronchial tubes and lungs. The main purpose of the respiratory system is to exchange gases. Breathing brings air into and out of the lungs, so that gas exchange can occur. Oxygen enters the bloodstream in the lungs by diffusion, and carbon dioxide leaves in the same way. This gas exchange specifically takes place in the alveoli, which are surrounded by capillary networks containing blood. When the blood arrives at the cells, the oxygen diffuses from the blood into the cells. At the same time, carbon dioxide diffuses from the cell into the blood.

The Epiglottis The function of the epiglottis is to allow the air inhaled while breathing to pass freely to the lungs. It covers the larynx to prevent the solids and liquids we consume from entering the windpipe (trachea). While swallowing, the tongue pushes the larynx downwards. This makes the epiglottis block the entrance to the windpipe. Once the swallowing is done, the epiglottis opens up for the air to pass through the windpipe again. If the epiglottis is absent or fails to function correctly, a person will not be able to swallow anything comfortably. He would cough and choke, as anything he would swallow would enter the windpipe. This is why it is said that a person should not talk or laugh while eating.

Breathing Involves the diaphragm (a large sheet of muscle underneath the lungs) and the muscles between the ribs. Is an involuntary process that we can override while talking but only temporarily. It is controlled by a part of the human brain that detects the concentration of CO2 in our blood

Non-smoker vs smoker LUNGS

Respiratory System Diseases Tuberculosis (bacterial) Cancers Emphysema Asthma

THE NERVOUS SYSTEM

What is the Nervous System? The control system that enables animals to detect a stimulus and coordinate a response Stimulus: changes in the body that are detected by your body Response: your body’s reaction to this stimulus

The nervous system is made up of the brain, spinal cord, and peripheral nerves. It senses the environment and coordinates an appropriate response. The core of the nervous system is the brain and the spinal cord. This is called the central nervous system. The central nervous system is protected from injury by bones and by cerebrospinal fluid. The peripheral nervous system consists of the nerves that carry the signals between the central nervous system and the body. It also relays instructions from the brain to other parts of the body to control many of the body’s functions and responses. Reflexes are actions that do not require the involvement of the brain: they occur without conscious thought. The spinal cord acts as a short cut for reflexes.

Types of Nerve cells (Neurons) Sensory neurons carry impulses from sensory receptors (eye, ear, nose, skin, tongue) to the brain Motor neurons carry impulses from the brain or spinal cord to muscles for movement or to glands for hormone secretion Interneurons link the sensory and motor neurons in the brain and spinal cord

How Does Communication Occur? Nerve cells are called neurons Neurons use electrical signals called impulses to communicate with other cells Nerve Connective tissue and bundles of neurons

Nerve Cell (receives message) (sends message)

Nervous System Disorders Multiple sclerosis – degeneration of myelin sheath; scar tissue builds Concussions – jars or shakes brain inside skull Damaged / severed spinal cords Parkinson’s disease Alzheimer’s disease