• Main Function:It releases hormones (chemical messengers) into the blood to signal other cells (target cells) to behave in certain ways. It is a slow but widespread form of communication.

Endocrine glands Release hormones into the bloodstream.

Hormones are chemicals released in one part of the body that travel through the bloodstream and affect the activities of cells in other parts of the body.

Consists of:

Interaction of GlandsThe hypothalamus is located in the brain and controls the release of hormones from the pituitary gland. It is an important link between the endocrine and nervous systems.

Interaction of GlandsThe brain and glands work together to maintain homeostasis through a process called negative and positive feedback mechanisms.

Endocrine System

Pituitary Gland

Pituitary Gland

Function: It secretes nine hormones that control all other endocrine glands.

-produces human growth hormone

- Disorders: Too much growth hormone can result in a condition called gigantism. Robert

Wadlow

Endocrine System

Pituitary Gland Thyroid Gland

Thyroid Gland• Hormone: Thyroxin• Function: plays a major role in the regulation the

body’s metabolism.• Disorders:

Hyperthyroidism-too much thyroxin; fast metabolism Hypothyroidism- too little thyroxin; slow metabolism

Goiter-lack of iron in diet, no thyroxin secretion, enlargement of thyroid gland

Endocrine System

Pituitary Gland Thyroid Gland

Adrenal Glands

Adrenal Gland

• Functions: -The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress.-Also regulates kidney function.

Endocrine System

Pituitary Gland Thyroid Gland

Adrenal Glands

Ovaries

Ovaries

• Functions: – Pair of reproductive organs found in

women that produce eggs.– Also secrete estrogen and

progesterone, which control ovulation and menstruation.

Endocrine System

Pituitary Gland

Pineal Gland

Thyroid Gland

Parathyroid Gland

Thymus

Adrenal Glands

Pancreas

Ovaries

Testes

Testes• Functions:

– Pair of reproductive glands that produces sperm.

– Also secrete Testosterone to give the body its masculine characteristics.

Endocrine System

Pituitary Gland

Pineal Gland

Thyroid Gland

Parathyroid Gland

Thymus

Adrenal Glands

Pancreas

Ovaries

Testes

Pancreas [Islets of Langerhans]

Insulin:

Reduces levels of glucose in the blood• conversion of glucose to glycogen •promoting glucose absorption and use by body cells

Glucagon:

Increases levels of glucose in the blood

• causes liver to convert glycogen to glucose

Negative Feedback

• Is a type of self-regulation associated with endocrine regulation

Functions like a thermostat. Only activated when there is a need. Shuts off once that need has been met.

Negative Feedback

A B

                                                                                                                                                                                                          

If there is too much glucose in the blood, insulin converts some of it to glycogen

Glycogen

Insulin

Glucose in the blood

If there is not enough glucose in the blood, glucagon converts some glycogen into glucose.

Glycogen

Glucagon

Glucose in the blood

Time

Glucose Concentration

Meal eaten

Insulin is produced and glucose levels fall to normal again.

Glucose levels rise after a meal.

Normal

Failure of Homeostasis:[Islets of Langerhans]

Diabetes:

Islets of Langerhans don’t make enough insulin• Glucose in blood can’t be stored as glycogen •Blood levels of glucose INCREASE

The glucose in the blood increases.

Glycogen

Insulin

Glucose in the blood

But there is no insulin to convert it into glycogen.

Glucose concentration rises to dangerous levels.

Time

Glucose Concentration

Meal eaten

Insulin is not produced so glucose levels stay high

Glucose levels rise after a meal.

Diabetic

Positive Feedback

• Enhances an existing response– Child birth

Interaction of GlandsThe feedback the brain gets is from the information it collects as the hypothalamus monitors the bloodstream. Using this information, the brain knows what hormones to start and stop releasing.

Main Function: This communication system controls and

coordinates functions throughout the body and responds to internal and

external stimuli.

Our nervous system allows us to feel pain.

Consists of: brain, spinal cord, nerves and sense organs

Sense Organs: Eyes, Skin, Ears, Nose & Tongue

A nerve is an organ containing a bundle of nerve cells called neurons.

Neurons carry electrical messages called impulses throughout the body. Picture shows hundreds of

severed neuron axons

cellbody

muscle tissue

TYPICAL MOTOR NEURON

Axondendrite

synapse

cell body

Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons.

Neurotransmitters

Synapse (gap)

The message is transferred when RECEPTORS receive neurotrans-mitters.

(pinkspheres)

Parts of a Neuron1. Cell body: contains nucleus & most of the

cytoplasm

2. Dendrites: projections that bring impulses into the neuron to the cell body.

3. Axon: long projection that carries impulses away from cell body

1

32

travels dendrite towards axon

Parts of a Neuron1. Cell body: contains nucleus & most of the

cytoplasm

2. Dendrites: projections that bring impulses into the neuron to the cell body.

3. Axon: long projection that carries impulses away from cell body

1

32

Sensory

Neuron

Interneuron

Motor Neuron

Sensory Neuron

Interneuron

Motor Neuron

Muscle Contracts

Synapse

Synapse

Synapse

Sensory Sensory NeuronNeuron

carry impulses from sense organs to

spinal cord & brain

Fun Fact:

Where can the largest cells in the world be found?

The giraffe’s sensory and motor neurons! Some

must bring impulses from the bottom of their legs

to their spinal cord several meters away!!

InterneuronInterneuron

-processes impulses in brain and spinal

cord

- connect sensory and motor neurons

Motor Motor Neurons

carry impulses from the brain & spinal cord to

muscles & glands

Axon End

Axons branching out to muscle fibers

• 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 axons of Sensory neurons to the brain cells called Interneurons.

• The brain will then send an impulse through motor neurons to the necessary muscle or organs, telling it to contract.

A reflex is an involuntary

response that is processed in the spinal cord not

the brain.

Reflexes protect the body before the brain knows

what is going on.

Reflex Arc

Reflex Arc

Path reflex impulse travels

Sense Receptor SensoryNeuron

SPINAL

CORD

MotorNeuronMuscle/Gland

Human Nervous System

Central Nervous System Peripheral Nervous System

[CNS] [PNS]

Brain & Spinal Cord Nerves branching from thebrain and spinal cord

brain

Spinal Cord

Cerebellum

Cerebrum

Medulla Oblongata

Consists of: Brain and Spinal Cord

Cerebrum Voluntary or conscious activities of the body-learning, judgment

Cerebellum Coordinates and balances the actions of the muscles

Medulla Oblongata

(Brain Stem)

Controls involuntary actions like blood pressure, heart rate, breathing, and swallowing

Spinal Cord

The main communications link between the brain and the rest of

the body

Consists of: Sensory division

and Motor division

-includes all sensory neurons, motor neurons,

and sense organs

Subdivisions of PNSSomatic Nervous System:

• voluntary control• responsible for conscious body movement

Autonomic Nervous System:

• no voluntary control• serve internal organs• involved with: heart rate

blood flow breathing movements digestive system gland secretions

Autonomic Nervous System:

Sympathetic: “fight or flight”speed up body functions

Parasympathetic:slow down body functions

Concept Map

which consists of

is divided into

that make up

which is divided into

The Nervous System

Sensory nerves

Motor nerves

Autonomic nervous system

Somatic nervous system

Central nervous system

Peripheral nervous system

Sympathetic nervous system

Parasympathetic nervous system

Nervous vs. Endocrine System

Similarities:

• both involved with maintaining homeostasis• both secrete chemicals

Endocrine System: hormones Nervous System: neurotransmitter

Differences:

• NS response is much faster than ES response• ES response lasts longer than NS response• Nerve impulse transmitted by neuron, hormones transported by the blood