Animal Anatomy: Structure and Systems

• Animal anatomy is the study of the structure of animal bodies
• Physiological functions refer to the processes that allow the body to work properly
• Organ systems are groups of organs that work together to perform specific functions

Anatomy and Structural Hierarchy

• Anatomy examines the structural organization of living organisms
• It ranges from macroscopic (gross) to microscopic levels
• Chemical level: Atoms combine to form molecules
• Cellular level: Molecules form organelles like the nucleus and mitochondria, which make up cells
• Tissue level: Similar cells and surrounding materials make up tissues
• Organ level: Different tissues combine to form organs
• System level: Organs working together to perform a common function
• Organismal level: Organ systems functioning together to form the whole organism

Major Tissue Types

• Epithelial tissue covers body surfaces, lines body cavities, and forms glands
• Connective tissue supports, connects, and separates different types of tissues and organs
• Muscle tissue is responsible for movement
• Nervous tissue enables communication via electrical and chemical signals

Organ Systems Overview

• The integumentary system includes skin, hair, and nails
• It provides protection, regulates temperature, and has cutaneous receptors
• The skeletal system protects and supports body organs
• It provides a framework for muscle movement and is the site of blood cell formation
• The muscular system allows environmental manipulation, locomotion, and facial expression
• It maintains posture and produces heat
• The nervous system is a fast-acting control system of the body
• It responds to internal and external changes by activating muscles and glands
• The endocrine system consists of glands that secrete hormones
• These hormones regulate growth, reproduction, and nutrient use (metabolism)
• The cardiovascular system transports blood, which carries oxygen, carbon dioxide, nutrients, and wastes
• The heart pumps blood
• The lymphatic system picks up fluid leaked from blood vessels and returns it to blood
• It disposes of debris and houses white blood cells (lymphocytes) involved in immunity
• The respiratory system keeps blood supplied with oxygen and removes carbon dioxide
• These exchanges occur through the air sacs of the lungs
• The digestive system breaks down food into absorbable units that enter the blood
• Indigestible foodstuffs are eliminated as feces
• The urinary system eliminates nitrogenous wastes and regulates water, electrolyte, and acid-base balance
• The male reproductive system's main function is the production of offspring
• Testes produce sperm and male sex hormone
• Ducts and glands deliver sperm to the female reproductive tract
• The female reproductive system's main function is the production of offspring
• Ovaries produce eggs and female sex hormones
• Remaining structures serve as sites for fertilization and fetal development
• Mammary glands produce milk

Physiological Functions: Key Concepts

• Physiology is the study of the function of living organisms and their parts
• It includes chemical and physical processes
• Homeostasis is maintaining a stable internal environment despite external changes
• It is essential for enzyme activity and cell survival
• Feedback mechanisms maintain homeostasis
• Negative feedback reduces the intensity of the original stimulus
• Positive feedback enhances or exaggerates the original stimulus

Cellular Physiology

• Cells are the basic structural and functional units of an organism
• Membrane transport includes passive (diffusion, osmosis) and active (requires energy) processes
• Cellular respiration produces energy (ATP)
• Protein synthesis involves transcription and translation

Control Systems

• The nervous system uses electrical signals for rapid communication
• The endocrine system uses chemical signals (hormones) for slower, more sustained communication
• The nervous system is a fast-acting control system of the body

Cardiovascular Physiology

• The heart pumps blood through vessels to deliver oxygen and nutrients
• Blood pressure is regulated by the nervous and endocrine systems
• Blood transports gases, nutrients, and hormones
• Blood removes waste products

Respiratory Physiology

• Gas exchange occurs in the lungs (oxygen in, carbon dioxide out)
• Breathing is controlled by respiratory centers in the brain
• The respiratory system keeps blood constantly supplied with oxygen and removes carbon dioxide

Digestive Physiology

• Digestion breaks down food into absorbable molecules
• Absorption occurs in the small intestine
• The digestive system breaks down food into absorbable units that enter the blood for distribution to body cells
• Indigestible foodstuffs are eliminated as feces

Renal Physiology

• The kidneys filter blood and regulate water and electrolyte balance
• Urine is produced to eliminate wastes
• The urinary system eliminates nitrogenous wastes from the body

Endocrine Physiology

• Glands secrete hormones that regulate various functions
• Hormones travel in the bloodstream to target tissues

Reproductive Physiology

• Gametes (sperm and egg) are produced
• Fertilization leads to the development of a new organism

Musculoskeletal Physiology

• Muscles contract to produce movement
• Bones provide support and leverage for muscles

Immune System Physiology

• The immune system defends against pathogens
• It includes innate and adaptive immunity

Integration of Organ Systems

• Organ systems work together to maintain homeostasis
• For example, the respiratory and cardiovascular systems work together to deliver oxygen to tissues
• The digestive, endocrine, and cardiovascular systems work together to provide energy to cells