Respiratory System

Respiratory System

• GAS EXCHANGE!!!• The path air takes:

– Mouth or nose → pharynx (throat) → larynx → trachea (windpipe) → 2 bronchi → lungs

– Epiglottis

• The air must be cleaned:– Lungs, nasal cavity, trachea, and bronchi are

lined with ciliated cells that secrete mucus

Respiratory System

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Respiratory System

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Digestive System

• The Mouth → The Stomach → The Small Intestine → The Large Intestine → The Rectum

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Digestive System

• The Mouth:– Mechanical Digestion (chewing) followed by chemical digestion

(Enzymes in your saliva)• Esophagus:

– muscular tube connecting mouth and stomach, food is moved by Peristalsis

• Stomach:– muscular, pouch-like enlargement of the digestive tract– both mechanical and chemical digestion– muscles churn the food– Inner lining contains millions of glands that secrete gastric juice

(hydrochloric acid and pepsin)– 2-4 hours later: consistency of tomato soup and on to the small

intestine

Digestive System• Small Intestine

– Muscular tube about 6 meters long– Digestion is completed here (mechanical and chemical)

• Pancreas– Secretes enzymes and hormones

• Enzymes go to the small intestine where they digest carbohydrates, proteins, and fats

• Liver– Many functions, but one is the production of bile, which helps break down fats

• From the liver bile goes to the Gall Bladder where it is stored until needed• Food is absorbed by the villi (link between digestive and circulatory)• 3-5 hours

• Large Intestine (Colon)– Indigestible material now passes into the large intestine– Water Absorption– Appendix (no use now but was important to herbivorous ancestors)– Vitamin synthesis by Anaerobic bacteria (B and K), bacteria also keeps harmful

bacteria from colonizing– 18-24 hours and out through the rectum and anus– Whole trip took 24-33 hours

Endocrine System

• Controls your body along with the nervous system• Made up of endocrine glands which release chemicals

(hormones) directly into your blood stream• Maintains homeostatis (along with nervous system)

– Coordination is via the hypothalamus (in the brain)– Hypothalamus controls the pituitary gland

• Pituitary gland releases hormones or stimulates other glands to release theirs

• Other glands include the thyroid gland, the adrenal glands, and glands associated with reproduction

• Hormones give cells in your body messages regarding your metabolism, growth, development, and behavior

Endocrine System

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Nervous System

• Controls everything!• Neurons are the basic unit of the nervous system

– Conduct impulses throughout the nervous system– Composed of three parts: cell body, dendrites, and an axon

Nervous System• Three types of neurons:

– Sensory neurons• Carry impulses from the body to the spinal cord and brain

– Motor neurons• Carry response impulses away from brain and spinal cord to a muscle or

gland– Interneurons

• Found within the brain and spinal cord • Process impulses and pass response to motor neurons

• Neurons lie end-to-end but do not actually touch– The space between one neuron’s axon and another’s dendrites is called

a synapse• Brain and spinal cord make up the central nervous system• The nervous system that carries messages to and from the central

nervous system is called the peripheral nervous system

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Nervous System

• The main control center: The Brain!

• Three regions:– Cerebrum

• Two hemispheres controlling intelligence, memory, language, skeletal muscle movements, and senses

– Cerebellum• Located at the back of the

brain• Controls balance, posture,

and coordination– Brain stem

• Medulla oblongata: controls involuntary activities such as breathing and heart rate

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