Digestive System

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Questions and Answers

What is the primary function of the esophagus in the digestive system?

To store bile from the liver

To break down food into smaller molecules

To absorb nutrients into the bloodstream

To transport food from the throat to the stomach (correct)

What is the term for the muscular movement of the esophagus that helps move food down into the stomach?

Ingestion

Absorption

Peristalsis (correct)

Digestion

In which part of the digestive system does food stay for approximately 4 hours?

Esophagus

Small intestine

Stomach (correct)

Large intestine

What is the function of the villi in the small intestine?

To absorb small nutrient molecules Signup and view all the answers

Which organ produces digestive juices that are added to the small intestine?

Liver and pancreas Signup and view all the answers

What is the term for the partially digested food that forms in the stomach?

Chyme Signup and view all the answers

What is the primary function of the Cerebrum?

Responsible for voluntary activities of the body Signup and view all the answers

What is the approximate speed at which messages travel through the nerves?

270 mph Signup and view all the answers

What is the primary function of the muscular system?

To facilitate movement Signup and view all the answers

Which type of muscle is found in the digestive tract and blood vessels?

Smooth muscles Signup and view all the answers

How many neurons are present in the human body?

100 billion Signup and view all the answers

What is the term for the substance stored in muscles that provides energy?

ATP Signup and view all the answers

What is the function of the hypothalamus?

Producing hormones Signup and view all the answers

Which part of the brain controls the opposite side of the body?

Left half of the brain Signup and view all the answers

What happens when muscles are overworked and lack oxygen?

Lactic acid is released, causing muscle ache Signup and view all the answers

What is the largest muscle in the human body?

Gluteus maximus (buttocks) Signup and view all the answers

What is the function of the Endocrine System?

Regulating body activities Signup and view all the answers

What is the main function of villi in the small intestine?

Increasing the surface area for nutrient absorption Signup and view all the answers

What is unique about how skeletal muscles work?

They work in opposing pairs to produce movement Signup and view all the answers

What is the primary function of the lungs in the respiratory system?

Moving air in and out of the lungs Signup and view all the answers

Which of the following is NOT a major structure in the excretory system?

Liver Signup and view all the answers

What is the role of the diaphragm in the respiratory system?

Enabling the lungs to expand and contract Signup and view all the answers

What happens to oxygen in the process of gas exchange in the lungs?

Moves from the lungs into the blood Signup and view all the answers

What is the role of the anus in the digestive system?

Controlling the release of solid wastes from the body Signup and view all the answers

What is the primary function of the hormone produced by the thyroid gland?

Controlling appetite and metabolism Signup and view all the answers

Which gland is responsible for producing the hormone estrogen?

Ovary Signup and view all the answers

What is the role of the thymus gland in the endocrine system?

T-cell development for fighting diseases Signup and view all the answers

What is the primary function of the hormone produced by the pineal gland?

Regulating sleep and wake cycles Signup and view all the answers

What is the effect of aging on hormone production in the body?

The body produces less of some hormones as a person ages Signup and view all the answers

How do hormones reach their target organs in the body?

Through the circulatory system Signup and view all the answers

Study Notes

The Central Nervous System

The brain is the main switching area of the central nervous system
The brain is divided into: Cerebrum (responsible for voluntary activities), Cerebellum (coordinates muscle movement and balance), and Brain Stem (consists of the pons and the medulla oblongata)
The left half of the brain controls the right half of the body and vice-versa
The human brain is more powerful and complicated than the world’s biggest computer
The human body has over 100 billion neurons
The brain can receive over 100,000 signals per second
Messages whiz through the nerves at up to 270 mph

The Peripheral Nervous System

Receives information from the environment and relays commands from the CNS to the organs and glands

The Endocrine System

Regulates body activities, temperature, metabolism, development, and reproduction
Maintains homeostasis and regulates other organ systems
The body makes over 20 hormones, each with a different job to do
Hormones can affect the way a person feels
As a person ages, the body makes less of some hormones
Major endocrine glands: hypothalamus, pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovary (female), testis (male), and pineal

Glands and Hormones

Pineal gland: produces melatonin, controls sleep and wake cycle
Thyroid gland: produces thyroxine, controls appetite and metabolism
Adrenal gland: produces adrenaline, deals with stressful situations
Thymus gland: produces thymosin, involved in T-cell development (fight diseases)
Ovary: produces estrogen, involved in female reproduction
Testis: produces testosterone, involved in male reproduction

The Digestive System

Function: to change food into simpler molecules that can be absorbed into bloodstream and used by the body
Major organs: mouth, esophagus, stomach, small intestine, large intestine
Mouth: where food enters the body
Esophagus: muscular tube that connects throat to stomach, moves food down by squeezing (peristalsis)
Stomach: muscular bag where chemical and mechanical digestion continue, food stays here ~4 hours, changes to chyme
Small intestine: tube nearly 7 meters long where digestive juices from liver and pancreas are added, absorbs small nutrient molecules
Large intestine: absorbs water from undigested food, where unabsorbed materials become more solid
Rectum: where solid wastes (feces) are stored
Anus: muscles control the release of solid wastes from the body

The Muscular System

Function: movement
Major muscle types: skeletal (attached to bones for voluntary actions), smooth (found in the digestive tract and blood vessels for involuntary actions), and cardiac (heart muscle cells are involuntary)
Skeletal muscles work in opposing pairs
Muscles can only pull – they cannot push
Energy is stored in the muscles in a chemical called ATP
Lactic acid is released when the muscles are overworked and lack O2, making the muscles hurt or ache
Muscles are attached to bones by tendons
The biggest muscles in the body are the gluteus maximus muscles (buttocks), but the muscle that can exert the most force is the masseter (jaw muscle)

The Respiratory System

Major structures: lungs, nose, mouth, trachea
Functions: moves air into and out of lungs, controls gas exchange between blood and lungs
Bronchi branch to air sacs known as alveoli, where gas exchange occurs
The respiratory system links to the circulatory system to provide cells with oxygen and remove carbon dioxide

The Excretory System

Functions: removes cellular wastes from blood and the body
Major structures: kidneys, urinary bladder, ureters, urethra, skin, lungs
Wastes and water diffuse out of the blood into filters in the kidney. The kidneys form the liquid waste, URINE.

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Description

Test your knowledge of the digestive system, including its function, major organs, and the process of breaking down food into simpler molecules. Learn about the role of the mouth, esophagus, stomach, small intestine, and large intestine in digestion.