Biology Chapter 40: Animal Form and Function

Chapter 40: Basic Principles of Animal Form and Function

• This chapter covers fundamental concepts of animal form and function.
• Animals' bodies are hierarchically organized, from cells to tissues, organs, and organ systems.
• Interstitial fluid fills the spaces between cells in vertebrates, facilitating material movement into and out of cells.
• Most animals have specialized cells organized into tissues with diverse functions.
• Tissues combine to form organs, which work together in organ systems.

Organ Systems

• Digestive: Processes food (ingestion, digestion, absorption, and elimination).
• Circulatory: Distributes materials internally (blood, vessels).
• Respiratory: Facilitates gas exchange (oxygen and carbon dioxide).
• Immune/Lymphatic: Defends the body against infections and cancer.
• Excretory: Removes metabolic wastes (regulation of osmotic balance).
• Endocrine: Coordinates body activities through hormones.
• Reproductive: Involved in reproduction.
• Nervous: Coordinates body activities, detects stimuli and formulates responses.
• Integumentary: Protects against injury and infection; thermoregulation.
• Skeletal: Provides support and protection; movement.
• Muscular: Responsible for movement.

Tissue Structure and Function

• Tissues have unique structures suited to their functions.
• Tissues fall into four categories: epithelial, connective, muscle, and nervous.

Epithelial Tissue

• Epithelial tissue covers the body's exterior and lines internal organs and cavities.
• Epithelial tissues are classified based on cell layers (simple or stratified) and cell shapes (cuboidal, columnar, squamous).
• Specialised epithelial tissues include simple columnar (digestive tract), pseudostratified ciliated columnar (respiratory tract). transitional/uroepithelial (urinary bladder).

Connective Tissue

• Connective tissues bind and support other tissues.
• Contain scattered cells within an extracellular matrix.
• The matrix consists of fibers (collagenous, elastic, reticular) within a liquid or semi-solid ground substance.
• Loose connective (binding epithelia to underlying tissues), cartilage (strong support), fibrous connective (tendons and ligaments).
• Connective tissue types include adipose, blood, bone, loose, and dense fibrous.

Muscle Tissue

• Muscle tissue consists of long fibers that contract in response to nerve signals.
• Three types of muscle are skeletal (voluntary movement, attached to bones), smooth (involuntary movement, lines internal organs), and cardiac (contractions in the heart).

Nervous Tissue

• Nervous tissue senses stimuli and transmits signals throughout the body.
• Contains neurons (transmit nerve impulses) and glial cells (support and nourish neurons).

Coordination and Control

• Body functions are coordinated by the endocrine and nervous systems.
• The endocrine system uses hormones to transmit chemical signals through the blood, and have slow-onset long-lasting effects.
• The nervous system rapidly transmits information to specific locations between neurons, muscle cells, and endocrine cells.

Homeostasis

• Organisms use homeostasis to maintain a stable internal environment despite external changes.
• Body temperature, blood pH, and glucose concentration are regulated in humans.
• Homeostasis regulation often involves negative feedback mechanisms, where responses reverse a trend back to a set point.

Thermoregulation

• Thermoregulation is the process maintaining internal temperature within a tolerable range.
• Endotherms generate heat metabolically (birds and mammals).
• Ectotherms gain heat from external sources (most invertebrates, fish, amphibians, and reptiles).
• Insulation (fur, feathers, skin) & circulatory adaptations (vasodilation, vasoconstriction) and cooling mechanisms (sweating, panting) are involved.
• The hypothalamus controls thermoregulation.

Other Important Concepts

• Pyrogens are substances that reset the body's thermostat in response to infection, causing fever.
• Negative feedback mechanisms act to maintain a steady state or internal balance.