Nutrition and Digestion

Question 1

Herbivore

Answer 1

An herbivore is an animal that primarily consumes plants as its main source of food.

Question 2

Carnivore

Answer 2

A carnivore is an animal that primarily consumes meat as its main source of food.

Question 3

Omnivore

Answer 3

An omnivore is an animal that consumes both plants and meats.

Question 4

Ingestion

Answer 4

Eating.

Question 5

Digestion

Answer 5

Breakdown of food into molecules small enough for the body to absorb.
Digestion begins with mechanical processes such as chewing.
Polymers become monomers because of digestive enzymes. When they are small enough, they can be absorbed by cells.

Question 6

Absorption

Answer 6

Uptake of small nutrient molecules by cells lining the digestive tract.

Question 7

Elimination

Answer 7

Disposal of undigested materials left over from food.

Question 8

Chemical digestion

Answer 8

Happens through hydrolysis (addition of water molecules), these reactions break down large molecules.

Digestive enzymes:

Pepsin: breaks down protein

Amylase: breaks down carbohydrates

Lipas: breaks down fats.

Question 9

Gastrovascular cavity

Answer 9

A digestive chamber found in simple animals like cnidarians and flatworms. It serves both digestive and circulatory functions. Food enters through a single opening, digestion occurs internally, and nutrients diffuse directly to cells lining the cavity. Undigested material is expelled through the same opening.

Question 10

Alimentary canal (or digestive tract)

Answer 10

A long, hollow tube that extends from the mouth to the anus and is responsible for the digestion and absorption of food. It includes organs such as the mouth, esophagus, stomach, small intestine, large intestine, and anus. The alimentary canal processes food through mechanical and chemical digestion, extracting nutrients and eliminating waste.

Question 11

Mouth (oral cavity)

Answer 11

Where food is ingested and digestion starts. Mechanical digestion begins here as the 32 teeth cut, smash and grind the food.

Question 12

Salivary glands

Answer 12

Chemical digestion begins in the mouth with secretion of saliva from salivary glands.
Saliva contains the digestive enzyme amylase which breaks down starch.

Question 13

Tounge

Answer 13

Muscle in mouth with swallowing moves food into the pharynx.

Question 14

Pharynx

Answer 14

A muscular tube located behind the mouth and nasal cavity, connecting them to the esophagus and the trachea. It plays a vital role in both the digestive and respiratory systems, serving as a passageway for food, liquids, and air. The pharynx helps direct food to the esophagus during swallowing and prevents food from entering the trachea (windpipe) by closing off the airway with the epiglottis.

Question 15

Esophagus

Answer 15

A muscular tube connecting the throat (pharynx) with the stomach. It serves as a conduit for food and liquids to pass from the mouth to the stomach through a series of coordinated muscle contractions called peristalsis. The esophagus has specialized muscles at both ends, the upper esophageal sphincter (UES) near the throat and the lower esophageal sphincter (LES) near the stomach, which help prevent the backflow of food and stomach acid.

Question 16

Gastric juice

Answer 16

A digestive fluid secreted by the gastric glands in the lining of the stomach. It is primarily composed of hydrochloric acid (HCl), enzymes (such as pepsin), mucus, and intrinsic factor. Gastric juice plays a crucial role in the digestion of food in the stomach by breaking down proteins into smaller peptides and amino acids, aiding in the absorption of certain nutrients, and killing bacteria ingested with food.

Question 17

Chyme

Answer 17

A semi-fluid mixture of partially digested food and gastric juices formed in the stomach during digestion. It is the result of mechanical and chemical digestion processes in the stomach, where food is churned and mixed with gastric secretions. Chyme is gradually released from the stomach into the small intestine for further digestion and absorption of nutrients. Its consistency and composition facilitate efficient absorption of nutrients by the intestinal lining.

Question 18

Small intestine

Answer 18

A long, coiled tube located between the stomach and the large intestine, divided into three sections: the duodenum, jejunum, and ileum. It receives partially digested food (chyme) from the stomach. Digestive enzymes from the pancreas and bile from the liver (stored in the gallbladder) are secreted into the duodenum to aid in the breakdown of carbohydrates, fats, and proteins. Nutrient absorption primarily occurs in the small intestine, facilitated by finger-like projections called villi and microvilli lining its walls..

Question 19

Microbiome

Answer 19

The diverse community of microorganisms residing in a specific environment, such as the human body. In humans, the microbiome, particularly in the gut, aids in digestion by assisting in the breakdown of certain nutrients. It also contributes to immunity and metabolism. Comprising bacteria, fungi, viruses, and archaea, its balance is crucial for overall health.

Question 20

Large intestine

Answer 20

The final portion of the gastrointestinal tract, consisting of the cecum, colon, rectum, and anus. It follows the small intestine in the digestive process and is primarily responsible for absorbing water and electrolytes from undigested food residues, forming feces. The colon, the largest part of the large intestine, further compacts waste material and absorbs water, while the appendix, a small pouch attached to the cecum, may play a role in immune function but is not essential for digestion. The rectum stores feces until they are expelled through the anus during defecation. The large intestine also houses a diverse microbial community, contributing to the fermentation of indigestible carbohydrates and the synthesis of certain vitamins.

Question 21

Calorie

Answer 21

A unit of energy commonly used to measure the energy content of food and the energy expenditure of the body. One calorie (cal) is defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius. In nutrition, the term “calorie” typically refers to kilocalories (kcal), where one kilocalorie equals 1000 calories.

Question 22

Metabolic rate and BMR

Answer 22

Metabolic rate refers to the overall rate at which the body expends energy for all physiological processes, including basal metabolic rate (BMR). BMR specifically represents the minimum amount of energy required to sustain basic bodily functions while at rest and in a fasting state, typically measured in calories per unit of time.

Question 23

Malnutrition

Answer 23

A condition resulting from an inadequate or imbalanced intake of nutrients, leading to deficiencies, excesses, or imbalances in the body’s nutritional status. Malnutrition can manifest as undernutrition, where there is a deficiency of essential nutrients.