AS103 Principles of Animal Science Homeostasis

Introduction to Anatomy and Physiology Study of the structures of the body Physiology Study of the functions of cells, tissues, organs, organ systems, and organisms

Levels of Organization

Chemical and Cellular Organization Chemical level Atoms, molecules, macromolecules Nucleic acids, Proteins, Carbohydrates, Lipids Cellular level Cell The functional and structural unit of life Basic and specialized functions Specialized function requires differentiation

Tissue Level of Organization Cells of similar shape and specialized function Four major tissue types Muscle Specialized for contracting and generating tension Nervous Specialized in impulse production and transmission Connective Specialized for connecting and supporting Epithelial Specialized for surface lining and exchange

Organs and Organ Systems Organ level Composed of two or more tissues that perform a common function Organ systems level Composed of two or more organs that work to perform a common function that is essential to survival Digestive, respiratory, cardiovascular The human body contains 11 systems

The Organism Collection of body systems working together to maintain life. Strive to maintain an internal balance Homeostasis

Homeostasis The maintenance of a stable internal environment. 37 degrees C, pH 7.3-7.4 Other factors that are regulated? The internal environment is made up of the extra cellular fluid or ECF Cells that are isolated from the external environment can still exchange materials with the ECF

Homeostatic Control Systems Network of body components that operate to maintain a given factor in the internal environment relatively constant around an optimal level Local (intrinsic) controls Inherent, or built into a particular organ Systemic (extrinsic) controls Outside of an organ Involves neural and endocrine regulation Coordinates various organs and systems

Negative Feedback Loops Maintain homeostasis by detecting a deviation from a set point and act to restore that set point Four components of a negative feedback loop Controlled variable Sensor Control center Effector

Other Regulatory Mechanisms Positive feedback loops Continues increasing a change Controlled variable moves in one direction Uterine contractions Feed forward mechanisms Anticipate change and responds to that change before it happens

Homeostasis What is Homeostasis? The maintenance of constant conditions in fluid surrounding cells (extracellular fluid) or internal environment by the integrated actions of various organs within the animal’s body Failure in homeostasis results in disease or death

How is homeostasis achieved? Homeostasis results from the work of different systems of organs with specific functions in the body

Systems and their functions Respiratory system- carries O2 from the environment lungs blood ECF CO2 from cells, ECF, blood, lungs, outside Provision of O2 coupled with removal of CO2 from tissues allows for efficient cell growth and metabolism Thus encourages maintenance of a relatively constant internal environment.

Systems and functions Circulatory system – carries blood throughout the body Importance in the establishment of homeostasis is through providing a passage and medium for transport for various factors within the body of the animal Digestive System – allows for digestion and absorption of food Digested food nutrients are used for cell growth and metabolism By providing these nutrients the digestive system is therefore vital in homeostasis

Systems and functions Urinary system – role in homeostasis is achieved through regulation of water balance, elimination of waste products, maintenance of electrolyte balance, and modulation of metabolic functions of the body Kidneys play a dominant role in the regulation of homeostasis

Systems and their functions Endocrine System - Involved in the regulation of all physiological processes occurring within the body of the animal which include digestion, circulation, respiration and reproduction Nervous system – for short term, rapid adaptation for protection of the internal environment