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

• 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

Did you know…

- It takes about 20 seconds for a RBC to circulate the entire body

Components of Blood

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 -make up less than 1% of blood volume -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….

(from body)

(from body)

(to lungs)

(from lungs)

(to 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. 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

• 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

What is the Nervous System?

• 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

THE IMMUNE SYSTEM

• The immune system is our body’s protection system.

• It is designed to defend against bacteria, viruses, and toxins that invade your body.

• T cells signal the invasion

• B cells make antibodies (chemical fighters)

• Macrophages white blood cells that EAT

Lymph nodes • Lymph nodes are filled with white blood cells.

• Lymph nodes are located throughout the body and swell when you’re fighting an infection because they work harder and collect dead cells.

• The main job of the lymph nodes is to filter the lymph (clear fluid that comes from tissues) by eliminating antibody-coated bacteria.

Bone marrow • Bone marrow is the spongy tissue inside of bones

(i.e. hip, breast, skull, ribs, vertebrae, shoulder blades, humerus, and femur). It has blood stem cells which can develop into any type of blood cell.

Thymus gland • Precursor cells from the bone marrow travel

to the thymus gland and here they develop into lymphocytes (white blood cells). Theses white blood cells will produce antibodies that fight bacteria and viruses.

Spleen • Also produces lymphocytes

• Filters blood to removes old red blood cells

• Also removes antibody-coated bacteria

• Located in the upper-left part of the abdomen

Immune system disorders

• Primary immunodeficiency (born weak)

• Acquired immunodeficiency (becomes weak)

• Autoimmune disorders (destroys itself)

– ALS, multiple sclerosis, lupus, diabetes type 1

• Overactive immune system

– Allergies

– Anaphylactic shock

THE DIGESTIVE SYSTEM

• The digestive system is the organ system that takes

in food, digests it, absorbs the nutrients, and excretes the

remaining waste.

• The digestive system is made up of the

digestive tract and 3 accessory organs.

• The parts of the digestive system in

humans are shown here.

Know the parts!

THE DIGESTIVE TRACT The tube in which the food travels through as it is digested

(mouth, esophagus, stomach, small intestine, large intestine, rectum, anus)

THE ACCESSORY ORGANS (Liver, Gall bladder, Pancreas)

Mouth • Breaks down food mechanically (teeth and

tongue)

• Also breaks apart food chemically with saliva (enzymes and water)

• Saliva is produced in the epithelial tissue that lines the mouth

Esophagus • A tube connecting your mouth to your

stomach

• Surrounded by smooth muscle tissue which can contract/relax without conscious thought

• Nerve tissue controls muscle contractions

• Contractions slowly move along food

Stomach • Holds and churns food

• Lining of inside of stomach has cells that produce digestive enzymes and acid

• Layers of smooth muscle tissue contract to mix stomach contents

Small Intestine

• After stomach in digestive tract

• Composed of smooth muscle

• 6m long, and narrow

• Goblet cells secrete mucus

• Does most digestion of food, and almost all absorption of nutrients

Large Intestine • 1.5m long, and wider than small intestine

• Absorbs water after digestion

• Waste left-over goes to rectum where it is packed and stored temporarily

• Then anus, and out!

Accessory organs

Liver • Produces bile (which breaks down fat in food) Gallbladder •Where bile is stored Pancreas •Creates an enzyme called insulin to help regulate

the concentration of sugar in our blood (either helps store it or send it to cells)

Digestive System Disorders

• Cancers

• Ulcers

• Diarrhea

• Constipation

• Lactose intolerance

• Heartburn / Gastroesophageal reflux disease

• Irritable bowel syndrome

THE MUSCULOSKELETAL SYSTEM

Musculoskeletal system

Muscular system

Skeletal System

• The musculoskeletal system

includes all of the bones and

muscles in a body.

• It supports, protects, and moves

the body.

Function of the Skeletal System

• Protection

- protect vital organs in the body (eg. skull protects brain, spine protects spinal cord, ribs protect heart and lungs

• Blood-cell production

- bone marrow in large bones produce blood cells and releases them into the blood stream

• Mineral storage

- bones made up of calcium and phosphorus giving bones strength and rigidity

• Support for your muscles

• Movement

Components of the Skeletal System

• The skeleton is composed of 3 types of connective tissue.

– Bone

– Ligaments

– Cartilage

Bone

• The human skeleton is composed of 206 bones

• Hard and dense tissue

• Bone is composed of bone cells within a matrix of minerals (calcium, phosphorus) and collagen fibers

• If your diet is not high in minerals, your body will absorb Ca and P from your bones causing them to weaken

Structure of Bone

- Canals inside the bones contain nerves and blood vessels

- Only a small percentage of the bone tissue is actually living

Ligaments (connect bone to bone) - are strong tough elastic bands of connective tissue that

can stretch - Hold bones and movable joints together - surround the joint to give support and limit the joint's

movement

Cartilage

• hard but slippery tissue that covers the ends of bones where they meet to form a joint.

• made up of cells and collagen fibres and is wear-resistant

• helps reduce the friction of movement by allowing bones to glide over one another

• Absorbs the energy from the shock of physical movement

• Found in: – Ears, nose, esophagus, joints,

disks between vertebrae

Muscles

• Bones need muscles to move them

• There are about 600 muscles in the human body

• Made up of bundles of long cells called muscle fibres that contain specialized proteins

Muscle

Tendons (connect muscle to bone)

• another type of tough connective tissue on each side of a joint attach to muscles that control movement of the joint.

Types of Muscles

• Cardiac Muscle – involuntary

– in heart

• Smooth Muscle – Involuntary

– in lining of organs (stomach,

esophagus, uterus, intestines)

• Skeletal Muscle – voluntary

– Attached to bone (bicep, tricep, deltoid)

Antagonistic Muscles

• One contracts while the other relaxes

• Work together to move bones

• Ex. Bicep and tricep, hamstring and quadricep

Problems with the Musculoskeletal System

• Arthritis

• Osteoporosis

• Broken bones

• Torn ligaments

• Torn tendons