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 Glands The 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 Glands The brain and glands work together to maintain homeostasis through a process called negative and positive feedback mechanisms.

Endocrine System 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

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

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

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 Glands The 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

cell body muscle tissue TYPICAL MOTOR NEURON Axon dendrite 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. (pink spheres)

Parts of a Neuron 1.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 travels dendrite towards axon

Parts of a Neuron 1.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 3 2

Sensory Neuron Interneuron Motor Neuron Sensory Neuron Interneuron Motor Neuron Muscle Contracts Synapse

Sensory Neuron 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!!

Interneuron -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

Path reflex impulse travels Sense Receptor Sensory Neuron SPINALCORDSPINALCORD Motor Neuron Muscle/Gland

Human Nervous System Central Nervous System Peripheral Nervous System [CNS] [PNS] Brain & Spinal CordNerves branching from the brain and spinal cord

brain Spinal Cord Cerebellum Cerebrum Medulla Oblongata Consists of: Brain and Spinal Cord

CerebrumVoluntary or conscious activities of the body-learning, judgment CerebellumCoordinates 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 PNS Somatic 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