Transcript Nervous, Endocrine, Immune Systems

Nervous, Endocrine,
Immune Systems
Nervous System
MAIN FUNCTIONS:
1. Transmits impulses to organs throughout the body.
2. Responsible for sensing and responding to stimuli
in the environment.
STRUCTURE:
Consists of nerve cells called neurons.
Neurons are specialized for transmitting
electrical signals called nerve impulse.
Nervous System
Nerves and Muscles
There are 3 Types of Neurons:
1. Sensory neuron – sends messages from the body to the brain
2. Interneuron – connect sensory and motor neurons at the spinal cord
3. Motor neuron – sends messages from the brain to the body (muscles)
Nerves work together with muscles for movement. An impulse begins when one neuron is
stimulated by another neuron or by the sense organs. The impulse travels down the sensory
neuron to interneuron in the spinal cord & brain. The brain will then send an impulse through a
motor neuron to the necessary muscle or organ, telling it to contract.
Interneuron
Sensory
Neuron
Muscle
Fibers
Motor
Neuron
Nervous System - Disorders
DISORDER: Multiple Sclerosis is caused by
destruction of large patches on the protective
covering of the neuron. Small, hardened scars
appear along the axon which interferes with
the normal transmission of impulses. Normal
nerve function is slowed, and symptoms such as
double vision, muscular weakness, loss of
memory, and paralysis result.
Two Main Divisions of the
Nervous System – CNS & PNS
1. Central Nervous System (CNS)
Cerebrum
Consists of the brain & spinal cord
Part to label
Cerebrum
Voluntary or conscious activities of the body.
Site of intelligence, learning, judgment.
Cerebellum
Coordinates and balances actions of
the muscles
brain
Cerebellum
Brainstem
Spinal Cord
Function
Medulla
Oblongata
(brainstem)
Regulates the flow of information between the
brain & body. Regulation of blood pressure,
heart rate, breathing and swallowing.
Spinal cord
Main communication link between the brain & the
rest of the body. 31 pairs of spinal nerves
originate here. Some reflexes are processed
here.
2. Peripheral Nervous System (PNS): Consists of the sense organs (eyes, ears, skin, tongue,
and nose), cranial nerves, and all other peripheral nerves extending out from the spinal cord to the
body parts.
Endocrine System
MAIN FUNCTION: Affects/controls the actions of other
glands and organs by the secretion of hormones
HORMONES: Chemicals that cause a reaction in another part of
the body.
Glands and the Hormones they Release:
ENDOCRINE
GLAND
HORMONE
EXAMPLE
FUNCTION
DISORDERS
Pituitary
Gland
Growth
hormone (GH)
Controls growth
(usually stops being
released by late teens
Giantism – too much HGH
Pituitary Dwarfism – too little
or early twenties)
Thyroid Gland
Thyroxine
Controls or regulates
body’s metabolism
Pancreas
Insulin,
glucagon
Adrenal Gland Aldosterone,
cortisol
HGH
Hyperthyroidism – too
much thyroxin
Hypothyroidism – too little
thyroxin
Controls blood
glucose levels (levels
of glucose)
Diabetes mellitus – too
little insulin
Help prepare the
body for stress
Cushing Syndrome –
too much cortisol
Addison Disease – too
little cortisol
Pituitary Gland
Thyroid Gland
Pancreas
Immune System
MAIN FUNCTION: Protects the body from invading pathogens (infectious agents)
recognizes and destroys invaders that have entered the body
1st line of Defense Skin and
Secretions- keep
pathogens out of the
body
Skin & Body secretions –
• Mucus, saliva & tears contain an enzyme that
break down the cell walls of bacteria
• Oil and sweat are acidic and kill bacteria
2nd line of Defense
Inflammatory
Response
fights local
Inflammation – a nonspecific defense reaction to
tissue damage caused by injury or infection
Fever – elevated body temperature
infections
3rd line of Defense
SPECIFIC Response
Fights systemic
Infections -infections
that entered the
bloodstream
Antigens – A substance that triggers an immune response
Antibodies – Proteins that recognize and bind to antigens.
White Blood Cells- There is different types that fight off
infections in different ways.
T - Cells- type of white blood cell that is responsible for
recognizing new infections
Antigen
binding sites
Antigen
Antibody
Immune Problems
Allergies: inflammatory response caused by over-reaction
of the immune system to antigens
Asthma: severe allergic response which narrows airways
Autoimmune Disease - the immune system mistakes its
own body’s cells as foreign and attacks them.
Two Examples:
1. Multiple Sclerosis – Myelin sheaths on nerve cells are
attacked, slowing down nerve impulses.
2. Rheumatoid Arthritis - Joints are attacked causing
them to become inflammed.