Nutrition and Exchange Systems Quiz

Study Notes

Living organisms exchange substances with their environment for nutrition. This process differs between unicellular and multicellular organisms.
Unicellular organisms directly exchange substances with their surroundings.
Multicellular organisms use intermediary systems to exchange substances between cells and the external environment.

Several systems work together to exchange substances within the body. These systems include:
Digestive System: Breaks down food into simpler substances (nutrients), absorbs them, and passes them into the bloodstream.
Respiratory System: Takes in oxygen (O₂), and releases carbon dioxide (CO₂) from the blood.
Circulatory System: Carries nutrients and oxygen to cells and transports waste products to excretory organs.
Lymphatic System: Works with the circulatory system to transport substances.
Excretory System: Removes waste substances from the blood and expels them from the body.

The digestive tract is a long tube comprised of multiple parts: mouth, pharynx, esophagus, stomach, intestines, and anus.
Accessory digestive glands include salivary glands, liver, gall bladder, pancreas.
Mouth: Chewing (mechanical digestion) and saliva production (chemical digestion).
Pharynx: Passageway for food and air.
Esophagus: Transports food from the pharynx to the stomach.
Stomach: Churning and the secretion of gastric juices for chemical digestion, specifically proteins. Converts bolus into chyme.
Small Intestine: Secretes intestinal juices to further break down food and absorb nutrients. Three parts: duodenum, jejunum, ileum. Absorption through villi.
Large Intestine: Absorbs water from indigested material and forms feces.

Respiratory Tract: A system of tubes carrying air to and from the lungs. Parts include: nostrils, pharynx (with epiglottis), larynx, trachea, bronchi, and bronchioles.
Lungs: Spongy organs located in the rib cage, separated by a double membrane (pleura).
Nostrils: Warm and humidify inhaled air. Contain mucus and hairs for filtering.
Pharynx: Passageway for air and food.
Epiglottis: Flap that prevents food from entering the trachea.
Larynx: Contains vocal cords for sound production.
Trachea: Supported by cartilage rings, transports air.
Bronchi: Branches of the trachea into the lungs.
Bronchioles: Further subdivisions of bronchi.
Alveoli: Tiny air sacs in the lungs where gas exchange occurs.
Diaphragm: Muscle that controls breathing. Contracts for inhalation; relaxes for exhalation.

Gases (oxygen and carbon dioxide) move from areas of high concentration to areas of low concentration (diffusion).
Oxygen from inhaled air moves into the blood, and carbon dioxide from the blood moves into the lungs for exhalation.