Biology Chapter on Human Digestion

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Questions and Answers

Which feeding mechanism involves animals that consume large chunks of food?

Bulk-feeders (correct)

Fluid-feeders

Substrate feeders

Filter-feeders

What is the primary purpose of the large intestine in the human digestive system?

To secrete digestive enzymes

To absorb water and mineral salts (correct)

To transport food to the stomach

To perform enzymatic hydrolysis

What is the first step in the stages of food processing?

Absorption

Elimination

Mechanical Processing/Ingestion (correct)

Secretion of enzymes

How does food move from the pharynx to the stomach?

Via peristaltic movement Signup and view all the answers

Which organ aids in the digestion process by secreting bile?

Liver Signup and view all the answers

What type of feeder are aquatic animals like whales categorized under?

Filter-feeders Signup and view all the answers

Which part of the digestive system is primarily responsible for nutrient absorption?

Small intestine Signup and view all the answers

What occurs during the enzymatic hydrolysis stage of food processing?

Food is chemically broken down by enzymes Signup and view all the answers

What is the primary function of the small intestine?

Completes digestion and absorbs nutrients Signup and view all the answers

Which accessory organ produces bile to aid in fat digestion?

Liver Signup and view all the answers

What is the primary source of energy in the animal diet?

Carbohydrates Signup and view all the answers

How do animals primarily absorb nutrients?

Through a digestive system Signup and view all the answers

Which nutrient is used primarily for building cell membranes and providing insulation?

Fats Signup and view all the answers

What is the role of vitamins in the animal diet?

Support normal metabolism Signup and view all the answers

Which of the following is true about the absorption of water in the large intestine?

It forms feces for expulsion Signup and view all the answers

Which characteristic distinguishes animals from plants in terms of feeding mechanisms?

Animals are heterotrophic Signup and view all the answers

What distinguishes autotrophs from heterotrophs?

Autotrophs obtain energy from sunlight or chemicals. Signup and view all the answers

Which of the following macronutrients is NOT included in the list of essential nutrients for plants?

Iron Signup and view all the answers

How do plants obtain oxygen necessary for their survival?

Through photosynthesis from carbon dioxide. Signup and view all the answers

What happens if the soil is compacted or saturated with water?

Oxygen becomes unavailable to plants. Signup and view all the answers

What is an example of a nutritional adaptation in plants?

Parasitism by obtaining nutrients from a host. Signup and view all the answers

What mechanism do birds use for gas exchange?

Unidirectional airflow system with air sacs Signup and view all the answers

Which structure is responsible for gas exchange in plant leaves?

Stomata Signup and view all the answers

What adaptation helps animals at high altitudes with gas exchange?

More alveoli and capillaries in lungs Signup and view all the answers

What is the primary function of the integumentary exchange in invertebrates?

Gas exchange through the body surface Signup and view all the answers

Which of the following factors does NOT affect animal gas exchange?

Internal temperature regulation Signup and view all the answers

Which animal respiratory organ is adapted for aquatic gas exchange?

Internal gills Signup and view all the answers

How do bronchiole muscles affect airflow during asthma?

They contract, decreasing airflow Signup and view all the answers

What type of respiration method do amphibians primarily use?

Positive pressure breathing Signup and view all the answers

Which structure assists in gas exchange in aerial roots of some plants?

Lenticels Signup and view all the answers

What respiratory function does the nervous system regulate?

Breathing rate and depth Signup and view all the answers

What is a primary consequence of malnutrition?

Stunted growth Signup and view all the answers

How does diabetes primarily affect the body?

Affects the body's ability to regulate blood sugar Signup and view all the answers

What dietary habit is most strongly linked to hypertension?

High salt and fat intake Signup and view all the answers

Which condition results from long-term exposure to pollutants and affects lung function?

Chronic Obstructive Pulmonary Disease (COPD) Signup and view all the answers

What is one of the leading causes of illness among vulnerable populations?

Pneumonia Signup and view all the answers

Which condition is a significant health concern due to its link to poor dietary habits?

Chronic Lower Respiratory Diseases Signup and view all the answers

What is a major contributing factor to pneumonia-related mortality?

Poor immunity Signup and view all the answers

What leads to significant mortality rates in patients with hypertension-related diseases?

Heart attacks or strokes Signup and view all the answers

Study Notes

Types of Organisms Based on Nutrition

Autotrophs (Self-Feeders): Obtain energy from sunlight and chemicals to produce their own food. Examples include plants and chemosynthetic bacteria.
Heterotrophs: Cannot make their own food. Obtain energy from other organisms. Examples include animals and fungi.

Plant Nutrition

Plants need water, carbon dioxide, and sunlight to make carbohydrates (glucose) through photosynthesis.
Oxygen is also produced during photosynthesis and used by plants for cellular respiration.
Nutrient absorption occurs through specialized proteins in the plasma membrane of root cells.
Compacted or waterlogged soil can prevent plants from getting necessary oxygen.

Essential Nutrients

Macronutrients (0.5% of dry weight): Carbon, Oxygen, Hydrogen, Nitrogen, Potassium, Calcium, Magnesium, and Phosphorus.
Micronutrients (Trace amounts): Chlorine, Iron, Manganese, Zinc, Boron, Copper, and Molybdenum.

Nutritional Adaptations

Plants and soil microbes can form symbiotic relationships (e.g., nitrogen-fixing bacteria).
Symbiosis of plants and fungi can enhance phosphorus transfer.
Parasitism includes parasitic plants that depend on hosts for survival.
Predation involves insectivorous plants that attract and digest insects.

Animal Nutrition Feeding Mechanisms

Substrate feeders live on or in their food source (e.g., earthworms, caterpillars).
Filter feeders in aquatic environments feed on food particles or small organisms (e.g., whales, coelenterates).
Fluid feeders acquire nutrients from living hosts (e.g., mosquitoes, leeches, aphids).
Bulk feeders eat relatively large chunks of food, requiring adaptations like jaws, teeth, or tentacles (e.g., snakes, cats, humans).

Stages of Food Processing

Mechanical processing/ingestion
Secretion of digestive enzymes and other digestive aids
Enzymatic hydrolysis
Absorption
Elimination

The Human Digestive System

Food is broken down and absorbed in the mouth, esophagus, stomach, small intestine, and large intestine.
Accessory organs (e.g., liver, pancreas) aid in digestion.
The large intestine absorbs water and mineral salts from undigested food.
Remaining waste is expelled as feces.

Human Digestive System: Specific Processes

Mouth: Digestion begins where saliva containing amylase, softens food and breaks it down. The tongue forms the bolus, which is swallowed into the esophagus.
Esophagus: Peristaltic movement moves food to the stomach (5-10 seconds).
Stomach: Food stays 2-6 hours. Gastric juices continue digestion.
Small Intestine: Food moves through the pyloric sphincter to the duodenum, jejunum, and ileum. Bile from the liver and enzymes from the pancreas complete digestion. Nutrients are absorbed through villi into the bloodstream.
Accessory Organs: The liver produces bile to aid fat digestion. The pancreas produces hormones like insulin to regulate blood sugar. The gallbladder stores and releases bile.
Large Intestine: Absorbs water and mineral salts; remaining material forms feces which are expelled via the rectum and anus (defecation).

Nutritional Requirements for Animals

Water: Aids digestion, regulates body temperature, maintains pH, keeps tissues moist.
Carbohydrates: Major energy source (4 calories/gram).
Proteins: Building blocks for cells, muscles, and bones (4 calories/gram).
Fats: Build cell membranes, insulate tissues, and are an energy source (9 calories/gram).
Minerals: Maintain homeostasis (e.g., calcium for bones/teeth, trace minerals).
Vitamins: Organic molecules required for normal metabolism (fat-soluble A, D, E, K and water-soluble B, C).

Plant and Animal Nutrition Comparison

Feeding Mechanism: Plants are autotrophic (self-feeding), animals are heterotrophic (consume other organisms).
Nutrient Absorption: Plants absorb nutrients through roots and leaves; animals absorb through a digestive system.
Nutrient Requirements: Plants need macronutrients and micronutrients; animals need water, carbohydrates, proteins, fats, minerals, and vitamins.
Digestive Process: Plants use photosynthesis to produce glucose; animals use mechanical and enzymatic breakdown of food.

Gas Exchange in Plants

Plants do not "breathe" like animals but undergo gas exchange through stomata in leaves, lenticels in stems, root hairs, and pneumatophores in aerial roots.
Carbon dioxide produced during plant respiration may be used in photosynthesis.

Gas Exchange in Animals

Animals have specialized respiratory organs.
Invertebrates include integumentary exchange (e.g., flatworms, earthworms), external gills (e.g., aquatic insects, mollusks, crustaceans), and tracheal systems (e.g., insects, spiders).
Vertebrates include external gills (e.g., larval amphibians), internal gills (e.g., fish), and lungs (e.g., reptiles, birds, mammals).

Factors Affecting Animal Gas Exchange

Respiratory surface area and permeability
Partial pressure gradients
Surface-to-volume ratio
Ventilation mechanisms
Respiratory pigments

Breathing Mechanisms in Vertebrates

Amphibians use positive pressure breathing.
Birds use unidirectional airflow systems with air sacs.
Mammals use negative pressure breathing.

Coordination of Gas Exchange and Circulation

Oxygen diffuses from alveoli into blood, binding to hemoglobin.
Carbon dioxide diffuses from blood into alveoli to be exhaled.
The nervous system regulates breathing rate and depth.

Respiratory Adaptations

High altitude: larger hearts/lungs, hemoglobin with high O2 affinity
Diving: slower heartbeat, reduced circulation (except brain)
Humans at high altitude: more alveoli with capillaries in the lungs
Asthma: bronchiole muscles contract, increasing airflow resistance.
Emphysema: damaged alveoli, reduced respiratory function.
Pneumonia: lung inflammation and fluid buildup.

Common Health Conditions in the Philippines

Malnutrition: Inadequate intake of essential nutrients, leading to stunted growth, underweight, or deficiencies (e.g., anemia).
Diabetes: Linked to poor dietary habits, affecting the body's ability to regulate blood sugar. Complications include heart disease and nerve damage.
Hypertension: Linked to poor nutrition (high salt/fat intake), leading to cardiovascular diseases.
Chronic Obstructive Pulmonary Disease (COPD): Often caused by long-term exposure to pollutants (e.g., smoke or dust), affecting gas exchange in the lungs.
Pneumonia: An infection of the lungs that affects breathing, common in populations with poor immunity or malnutrition.

Top 3 Morbidity and Mortality in the Philippines

Pneumonia is a leading cause of illness and death, particularly among children and the elderly.
Hypertension-related illnesses (heart disease, stroke) are also significant.
Chronic lower respiratory diseases are a burden due to prolonged illness and disability.

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