The document discusses four major human organ systems - the nervous system, respiratory system, excretory system, and circulatory system. It provides details on the structure and functions of each system. The nervous system coordinates behavior and signal transmission using neurons and neural pathways. The respiratory system involves gas exchange in the lungs and respiratory structures. The excretory system maintains homeostasis by filtering and removing waste from the blood. The circulatory system uses the heart to pump blood through vessels to tissues throughout the body.

1. Human Organ Systems
(Four System has been represented)
1.Nervous System
2. Respiratory System
3. Excretory System
4.Circulatory System

2. NERVOUS SYSTEM

3. Nervous system
The nervous system is the part of an animal's body
that coordinates its behavior and transmits signals
between different body areas. In vertebrates it
consists of two main parts, called the central nervous
system (CNS) and the peripheral nervous system
(PNS). The CNS contains the brain and spinal cord.
The PNS consists mainly of nerves, which are long
fibers that connect the CNS to every other part of the
body, but also includes other components such as
peripheral ganglia, sympathetic
and parasympathetic ganglia, and the enteric nervous
system, a semi-independent part of the nervous
system whose function is to control the
gastrointestinal system.
At the cellular level, the nervous system is defined by
the presence of a special type of cell, called
the neuron, also known as a "nerve cell". Neurons
have special properties that allow them to send
signals rapidly and precisely to other cells. They send
these signals in the form of electrochemical waves
traveling along thin fibers called axons, which cause
chemicals called neurotransmitters to be released at
junctions to other neurons, called synapses. A cell
that receives a synaptic signal from a neuron (a
postsynaptic neuron) may be excited, inhibited, or
otherwise modulated. The connections between
neurons form neural circuits that can generate very
complex patterns of dynamical activity. Along with
neurons, the nervous system also contains other
specialized cells called glial cells (or simply glia),

4. Structure of Neuron
The nervous system is defined by the presence of
a special type of cell, the neuron (sometimes
called "neurone" or "nerve cell"). Neurons can be
distinguished from other cells in a number of
ways, but their most fundamental property is
that they communicate with other cells via
synapses, which are junctions containing
molecular machinery that allows rapid
transmission of signals, either electrical or
chemical. Many types of neuron possess
an axon, a protoplasmic protrusion that can
extend to distant parts of the body and make
thousands of synaptic contacts. Axons
frequently travel through the body in bundles
called nerves (in the PNS) or tracts (in the
CNS).

5. FUNCTIONS OF NERVOUS SYSTEM
 The ultimate function of the nervous system is to control the body, especially
its movement in the environment. It does this by extracting information from
the environment using sensory receptors, sending signals that encode this
information into the central nervous system, processing the information to
determine an appropriate response, and sending output signals to muscles or
glands to activate the response.
 At the most basic level, the nervous system sends signals from one cell to
others, or from one part of the body to others. There are multiple ways that a
cell can send signals to other cells. One is by releasing chemicals called
hormones into the internal circulation, so that they can diffuse to distant sites.
In contrast to this "broadcast" mode of signaling, the nervous system provides
"point-to-point" signals — neurons project their axons to specific target areas
and make synaptic connections with specific target cells. Thus, neural signaling
is capable of a much higher level of specificity than hormonal signaling. It is
also much faster: the fastest nerve signals travel at speeds that exceed 100
meters per second.

6. Reflexesandother
stimulus-response
circuits
The simplest type of neural circuit is a reflex arc, which
begins with a sensory input and ends with a motor
output, passing through a sequence of neurons in
between. For example, consider the "withdrawal reflex"
causing the hand to jerk back after a hot stove is
touched. The circuit begins with sensory receptors in
the skin that are activated by harmful levels of heat: a
special type of molecular structure embedded in the
membrane causes heat to change the electrical field
across the membrane. If the change in electrical
potential is large enough, it evokes an action potential,
which is transmitted along the axon of the receptor
cell, into the spinal cord. There the axon makes
excitatory synaptic contacts with other cells, some of
which project (send axonal output) to the same region
of the spinal cord, others projecting into the brain.
One target is a set of spinal interneurons that project
to motor neurons controlling the arm muscles. The
interneurons excite the motor neurons, and if the
excitation is strong enough, some of the motor
neurons generate action potentials, which travel down
their axons to the point where they make excitatory
synaptic contacts with muscle cells. The excitatory
signals induce contraction of the muscle cells, which

7. Respiratory System in
Humans

8. The respiratory system is the
network of organs and tissues that
help you breathe. It includes your
airways, lungs, and blood vessels.
The muscles that power your lungs
are also part of the respiratory
system. These parts work together to
move oxygen throughout the body
and clean out waste gases like
carbon dioxide

9. In easy words..
The system by which oxygen is taken into the
body and an exchange of oxygen and carbon
dioxide takes place; in mammals
the system includes the nasal passages,
pharynx, trachea, bronchi, lungs, nose.
The lungs and respiratory system allow us to
breathe. They bring oxygen into our bodies
(called inspiration, or inhalation) and send
carbon dioxide out (called expiration, or
exhalation). This exchange of oxygen and
carbon dioxide is called respiration.
The lungs are a pair of spongy, air-filled
organs located on either side of the chest
(thorax). The trachea (windpipe) conducts
inhaled air into the lungs through its tubular
branches, called bronchi. The bronchi then
divide into smaller and smaller branches

10. What are the 5 main functions of the respiratory system?
There are five functions of the
respiratory system.
Gas Exchange – Oxygen and Carbon
Dioxide.
Breathing – Movement of Air.
Sound Production.
Olfactory Assistance – Sense of
Smell.
Protection – From dust and microbes
entering body through Mucus production, cilia, and
coughing.

11. ProcessofRespiration
Organs specialized for breathing usually contain moist
structures with large surface areas to allow the diffusion of
gases. They are also adapted to protect the organism from
the invasion of pathogens along those surfaces.
The respiratory system begins in the nose, continues into
the pharynx and larynx, leads to the trachea which branch
to create bronchi, and finally down the bronchioles into the
lungs. This respiratory tree ends in puffy structures called
alveoli that are made of a single layer of squamous cells,
surrounded by a network of capillaries. Gas exchange occurs
within alveoli. Since external respiration in many
vertebrates involves lungs, it is also called pulmonary
ventilation. Changes to the volume and pressure in the
lungs are the primary driving forces for breathing.

12. Human Excretory System

13. Structureand
PartsofExcretory
System
Organs of excretion make up
the excretory system. They include the
kidneys, large intestine, liver, skin, and
lungs. The kidneys filter blood and form
urine. They are part of the
urinary system, which also includes the
ureters, bladder, and urethra.

14. Function And Process of Excretory System
The excretory system functions as the bulwark and balance to
the digestive system. While we consume food and drink to nourish the
body and provide energy, the excretory system ensures
that homeostasis is maintained, irrespective of changes to the nutritive
value of food.
It regulates the fluid balance of the body, maintaining adequate salt
and water levels. When there is excess water, it is removed through the
production of hypotonic urine. When we consume salty food or lose
water through perspiration, the concentration of urine is increased to
preserve the osmolarity of body fluids. The kidneys filter urea and other
waste products from the blood, which are then added to the urine
within the bladder. Other organs, such as the liver, process toxins but
put their wastes back into the blood. It is up to the kidneys to filter the
blood so that toxic substances do not accumulate. Parts of the
excretory system are also influenced by other body systems, such as
the muscular system and skeletal system. For example, the kidneys
secrete a hormone which tells the bones to produce more red blood cells.

15. Other Important functions of the Urinary
System!
 Maintain blood volume and
composition.
 Excrete nitrogenous waste.
 Urine formation.
 Hormone production.

16. HUMAN
CIRCULATORY
SYSTEM

17. WHAT IS THE CIRCULATORY SYSTEM?
• The circulatory system carries blood and dissolved substances to and from
different places in the body.
• The Heart has the job of pumping these things around the body.
• The Heart pumps blood and substances around the body in tubes called blood
vessels.
• The Heart and blood vessels together make up the Circulatory System.

18. THE HEART
This is the largest vein Vena
Cava . It brings deoxygenated
blood to the right side of the
heart from the body, except the
lungs.
Largest artery - Aorta
These are the arteries. They carry
oxygenated blood away from the
left side of the heart.
Coronary arteries , the
heart own blood
supply
2 Atriums
2Ventricles
The Heart has four chambers

19. THE
HEART
Artery to Head and Body
Vein from Lungs
Left Atrium
Valve
Left Ventricle
Vein from Head and Body
Right Atrium
Valve
Right Ventricle
Artery to Lungs

20. Our circulatory system is a double circulatory
system.
Lungs
Body Cells
The right side
of the system
deals with
deoxygenated
blood
The left side
of the system
deals with
oxygenated
blood

21. Surprise! ...
 You lose a lot of water just by breathing....
 Some people can hold their breath for more than 20 minutes. ...
 The common cold can be caused by hundreds of different viruses.
 When our brain senses a shortage of oxygen, it triggers us to take a long deep breath or to YAWN.
 The human bladder can stretch to hold about 400ml of urine.
 All the blood in our body is filtered 400 times through the kidneys every day
 Each kidney is about the size of your fist. ...
 There is a nervous system for controlling the body at rest
 Your nervous system can be hacked
 The circulatory system in the human body stretches 66,000 miles, more than two and a half times the
circumference of the Earth.
 Each second, we lose about 3 million red blood cells only to be replaced by the same number produced in
the bone marrow.
 The heart beats 2.5 billion times during the life of a 75-year-old.