Biology Chapter on Digestion and Circulation

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Questions and Answers

What is the primary role of glucagon in glucose regulation?

Inhibits the release of insulin

Promotes the uptake of glucose by cells

Stimulates the liver to produce glucose (correct)

Increases the storage of glucose in the liver

Which of the following is a feature of a closed circulatory system?

Blood is mixed with interstitial fluid

It allows for effective delivery of nutrients to larger organisms (correct)

Circulatory fluid is open to the environment

Blood flows freely in cavities

How does gas diffusion primarily occur in the lungs?

Between blood and the environment

Through active transport mechanisms

From high to low partial pressure (correct)

From low to high partial pressure

What is a significant limitation of diffusion as a means of material exchange?

It becomes inefficient over long distances Signup and view all the answers

What component does NOT belong to the basic components of a circulatory system?

Respiratory membrane Signup and view all the answers

Why do smaller organisms like flatworms not require tissue specialization?

They are in direct contact with their environment Signup and view all the answers

What happens to carbon dioxide in the gas exchange process?

It diffuses from cells into the blood where partial pressure is lower Signup and view all the answers

What is the role of the circulatory system in relation to homeostasis?

To link exchange surfaces with all body cells Signup and view all the answers

What is the primary function of mechanical digestion?

To grind food and increase its surface area for easier digestion Signup and view all the answers

Which process involves the breakdown of food outside the cell?

Extracellular digestion Signup and view all the answers

What is the role of amylase in digestion?

To break down starch into smaller polysaccharides and maltose 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

How does hydrochloric acid contribute to digestion in the stomach?

It kills bacteria and denatures proteins Signup and view all the answers

What structure enhances the absorption of nutrients in the small intestine?

Villi and microvilli Signup and view all the answers

What is the function of the hepatic portal vein?

To carry nutrient-rich blood from the intestine to the liver Signup and view all the answers

What occurs when pepsinogen is activated in the stomach?

It is transformed into pepsin to digest proteins Signup and view all the answers

Which function does the cardiovascular system serve in organisms such as annelids and vertebrates?

Distributes blood to different organs Signup and view all the answers

What type of circulatory system do insects and arthropods have?

Open circulatory system Signup and view all the answers

What process increases blood pressure by narrowing the arteriole walls?

Vasoconstriction Signup and view all the answers

Which of the following components are found in both arteries and veins?

Endothelium, smooth muscle, and connective tissue Signup and view all the answers

What feature is essential for effective gas exchange in the alveoli?

A moist surface and large surface area Signup and view all the answers

How is oxygen transported to the cells in mammals?

It flows through capillaries after being oxygenated in the lungs Signup and view all the answers

What is the primary role of capillary beds in the circulatory system?

To allow for the exchange of materials Signup and view all the answers

What happens during ventilation in the respiratory system?

Air is expelled from the lungs Signup and view all the answers

What happens during inhalation?

Negative pressure pulls oxygen into the lungs. Signup and view all the answers

How does the body respond to a decrease in blood pH?

The body exhales excess CO2 and inhales oxygen. Signup and view all the answers

What is the primary function of respiratory pigments like hemoglobin?

To facilitate a greater transport of oxygen. Signup and view all the answers

What does the hemoglobin dissociation curve indicate?

A slight change in partial pressure of O2 greatly affects oxygen delivery. Signup and view all the answers

What occurs during the Bohr shift when blood pH decreases?

Hemoglobin's affinity for oxygen decreases. Signup and view all the answers

How does double circulation benefit the body?

It separates oxygen-rich and oxygen-poor blood for efficient pumping. Signup and view all the answers

What role does cerebrospinal fluid play in homeostatic control of breathing?

It buffers against acidity changes and signals the brain. Signup and view all the answers

What effect does a higher blood pH have on hemoglobin's affinity for oxygen?

Hemoglobin has an increased affinity for oxygen. Signup and view all the answers

What is the primary function of B cells in the immune response?

Produce antibodies to fight antigens Signup and view all the answers

What is a required condition for the activation of T cells?

Interaction with a Helper T cell Signup and view all the answers

How do B cells recognize different antigens?

Through the variable region of their receptors Signup and view all the answers

What is the primary role of cytokines released by Helper T cells?

Activate macrophages and B cells Signup and view all the answers

Which immune response is primarily associated with T cells?

Cell-mediated immune response Signup and view all the answers

What triggers the proliferation of B cells after activation?

Cytokines released by Helper T cells Signup and view all the answers

Which type of immune cell is responsible for inducing apoptosis in infected cells?

Cytotoxic T cells Signup and view all the answers

Natural killer cells play a key role by doing which of the following?

Killing cells marked by antibodies Signup and view all the answers

What is the primary role of the nephron in the kidney?

It filters blood to form urine. Signup and view all the answers

Which of the following components is NOT included in the filtrate produced during filtration?

Red blood cells Signup and view all the answers

What process primarily occurs in the proximal tubule of the nephron?

Reabsorption of water and nutrients. Signup and view all the answers

How does the descending loop of Henle primarily function in reabsorption?

It reabsorbs water using aquaporins. Signup and view all the answers

In which part of the nephron is sodium chloride primarily reabsorbed?

Ascending loop of Henle. Signup and view all the answers

What effect does reabsorption have on the filtrate within the nephron?

It concentrates the contents of the filtrate. Signup and view all the answers

Which statement best describes the process of secretion in the nephron?

It removes certain substances from the blood into the filtrate. Signup and view all the answers

Which component does NOT regulate pH in the distal tubule?

Sodium ions. Signup and view all the answers

Study Notes

Nutrition and Digestive System

Animals ingest food, then digest, absorb nutrients, and eliminate waste.
Herbivores eat plants, carnivores eat meat, and omnivores eat both.
Autotrophs produce their own food (photosynthesis), while heterotrophs consume other organisms.
Essential nutrients are required for bodily functions but cannot be produced by the organism itself.
- Minerals (often needed in small amounts)
- Vitamins (13 essential for humans; fat and water soluble)
- Essential Fatty Acids (obtained from diet)
- Essential Amino Acids (many animals synthesize some, but require other ones in their diet)

Food Processing

Digestion involves mechanical breakdown (chewing) and chemical breakdown (enzymes that break down food into usable molecules).
Intracellular digestion breaks down food inside cells, while extracellular digestion breaks down food outside cells in a cavity.

Absorption

Small intestine has villi and microvilli, increasing the surface area for nutrient absorption.
Nutrients absorbed enter the bloodstream via the hepatic portal vein which delivers blood to the liver for nutrient processing.

Elimination

Large intestine absorbs water and forms feces.
Microbiome in the large intestine aids in digestion.
Animals have adaptations to digest cellulose through fermentation chambers.

Hormonal Control of Digestion

Leptin and Insulin regulate appetite and blood glucose levels.
PYY suppresses appetite after meals.
Ghrelin stimulates hunger.
Gastrin promotes gastric juice production.
CCK and Secretin regulate digestion of fats and neutralize chyme.

Cardiovascular Adaptations

Double circulation (two circuits of blood flow through the heart and lungs) are found in mammals and birds.
Mammals have four chambered heart
Single circulation in fish
Amphibians have 3 chambered hearts in which blood flow to the lungs and the body mix.

Respiratory Adaptations

Gills and lungs are for gas exchange
Gills use a countercurrent exchange system,
High-altitude animals have hemoglobin with a higher oxygen affinity.

Circulation and Gas Exchange

Circulatory system is essential for supplying cells with needed materials and removing waste.
Diffusion isn't efficient over long distances, and tissues must be specialized
Partial pressure drives gas exchange (oxygen flows from a higher partial pressure to lower, and carbon dioxide vice-versa).

Immune System

Immunity protects against pathogens (bacteria, viruses, and parasites).
Innate immunity is present in all animals and provides a first line of defense.
Adaptive immunity develops after exposure to various substances.

Blood Components

Many organisms use pigments to transport oxygen (hemoglobin, hemocyanin).
Hemoglobin's affinity for oxygen changes with pH, affecting oxygen delivery to tissues. (Bohr Shift)

Immunological Memory

Primary response: Initial exposure to an antigen.
Secondary response: Faster response due to memory cells following secondary exposure.

Osmoregulation and Excretion

Osmoregulation controls water balance.
Excretion removes waste products.
Conformers tolerate environmental changes in osmolarity, whereas regulators maintain a constant internal state.
Animals' types of nitrogenous waste vary (ammonia, urea, uric acid).

Vertebrate Excretory System

Kidney is the primary osmoregulation and excretion organ.
Nephrons are the functional units of the kidney.
Four steps: filtration, reabsorption, secretion, and excretion.

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Description

Test your knowledge on the key concepts of digestion and circulation in animals. This quiz covers the roles of various systems and processes involved in nutrient absorption, gas exchange, and homeostasis. Ideal for students studying biology at an introductory level.