Animal Sciences 142 - Anatomy and Physiology Study Notes
Introduction to Anatomy and Physiology
Course Overview: This course, Animal Sciences 142, focuses on the anatomy and physiology of domestic animals.
Learning Outcomes: After this lecture, students should:
Define anatomy and physiology.
Differentiate approaches to studying anatomy (microscopic vs. macroscopic anatomy).
Understand levels of biological organization (from atoms to organism).
Define characteristics of living organisms and the term homeostasis.
Describe anatomical planes, directional terms, and anatomical regions of domestic animals.
List the four basic types of body tissues.
Definitions of Anatomy and Physiology
Anatomy: The study of the structure or parts of living organisms. Examples include bones, muscles, and organs in vertebrates.
Physiology: The study of the functions of body parts. Example: Functions of the humerus, radius, and ulna (bones of the arm).
Complementarity of Structure and Function: The idea that the function of a structure is dependent on its anatomy.
Example: The knee (stifle joint) is composed of the femur, tibia, fibula, and patella. The structural arrangement allows specific movements (flexion and extension) while restricting others (beyond 180 degrees due to ligaments).
Approaches to Studying Anatomy
Gross Anatomy (Macroscopic Anatomy): The study of large body structures observed with the naked eye.
Systemic: we look at anatomy by the bodies systems
Regional: where we look at all the body structures in a particular region
Example: Dissection of a cat to observe muscles, heart, lungs.
Microscopic Anatomy (Microanatomy): The study of very small structures, often under a microscope.
Cytology: Study of cells.
Histology: Study of tissues.
Example: Microscopic examination of samples from diseased ears or tumors.
Developmental Anatomy: Examines changes in body structures throughout the life cycle, from fertilized egg to embryo, fetus, and neonate.
Physiology: The function of particular body organs or systems . Typically studied in live organisms, and (e.g., cardiovascular, endocrine, urinary).
Can do an anatomical study on a preserved specimen or even a dead animal.
Biological Organization Levels
Levels of Biological Organization:
Atom: Smallest particle of an element, exhibiting physical and chemical properties (e.g., gold).
Molecule: Combination of two or more atoms (e.g., water, H₂O).
Cell: Smallest structure showing all life characteristics (e.g., ability to reproduce, regulate physiological processes).
Cellular Organelles: Small structures within cells that perform specific functions (e.g., mitochondria for energy production, nucleus for genetic information).
Tissue: Groups of similar cells performing a specific function. Four main types:
Muscular Tissue: Facilitates movement.
Epithelial Tissue: Covers surfaces and lines cavities.
Connective Tissue: Supports and binds other tissues (e.g., blood, bone).
Nervous Tissue: Transmits information through electrical impulses.
Organ: Made of two or more tissue types functioning together (e.g., stomach for digestion).
Organ System: Groups of organs working together (e.g., digestive system includes the stomach, intestines).
Organism: A living individual (e.g., cat, dog, horse) composed of multiple organ systems.
Characteristics of Living Organisms
All living organisms:
Are made up of cells.
Have a high degree of organization.
Have a metabolism (the sum total of the chemical processes that occur in living organisms, resulting in growth, production of energy elimination of waste material), which includes:
Anabolism: Building smaller molecules into larger ones (e.g., protein synthesis).
when the body taked smaller molecules, and when energy is added it creates larger molecules
Catabolism (like a cat tearing shit into pieces: Breaking down larger molecules into smaller ones (e.g., digestion of starch into simple sugars).the reverse of anabolism. it breaks down a large molecule into smaller molecules and energy
Sexual Reprodution: Where a male and a female contribute their sperm and egg to fuse creating a fertilized egg which is known as a zygote. the zygote will develop into an offspring
generating genetically distinct offspring, because the offspring contains genes of both parent. this is important because recombination of genes helps organisms to deal with changing environments and makes them less prone to extinction.
Undergo growth and differentiation: From zygote to embryo to fetus to adult.
Maintain homeostasis, a stable internal environment despite external changes.
Example: Body temperature regulation through mechanisms (e.g., sweating / panting).
Growth and Differentiation
so we know that the sperm and the egg create a zygote when fused. but after this happens, the zygote will continuously divide until it creates and embryo
the embryo will morph into a neonate or a newborn. as it ages it wil change because it is still undergoing growth and differentiation until it becomes and adult.
the postnatal period is where the last characteristics of living organisms is called homeostasis
Homeostasis and Feedback Systems
Homeostasis: The body's ability to maintain stable internal conditions amidst an unstable environment (e.g., temperature, pH, pressure).
Feedback System: A process of monitoring controlled conditions. A system in which the response of the effector reverses the change in the controlled condition
Stimulus: A change in the internal environment (e.g., temperature rise).
Receptor: Monitors and sends input to the control center.
Control Center: Analyzes input and determines response.
Effector: Implements the response to counteract the change.
Negative Feedback System: The response reduces or reverses changes.
Example: Body temperature regulation—sweating or shivering.
Positive Feedback System: The response enhances the original stimulus.
Rare in mammals, example includes childbirth (contractions promote further contractions).
Anatomical Terminology
Standard Anatomical Position: Standing position, facing forward, arms at sides, palms facing forward.
Bilateral Symmetry: Organisms have equal right and left sides. Most domestic animals fall into this category.
Regional Terms
Muzzle: Front end (nose area).
Pole: Top of the head.
Withers: Dorsal area above shoulder blades (scapula).
Brisket: Area at the base of the neck between front legs.
Barrel: Trunk of the body formed by ribcage and abdomen.
Flank: Lateral surface of abdomen near hind legs.
Tail Head: Area where the tail joins the body.
Stifle Joint: Equivalent to the knee in humans; joint between femur and tibia.
Gaskin: Calf muscle in horses.
Fetlock: Metacarpal/metatarsal phalangeal joint in horses.
Directional Terms
Dorsal: Towards the back.
Ventral: Towards the belly.
Medial: Towards the midline of the body.
Lateral: Away from the midline.
Cranial: Towards the head.
Caudal: Towards the tail.
Proximal: Towards the body.
Distal: Away from the body.
Deep: Towards the center of the body.
Superficial: Towards the body surface.
Anatomical Planes
Dorsal Plane: Divides body into dorsal (back) and ventral (belly) halves.
Transverse Plane: Divides body into cranial and caudal parts.
Sagittal Plane: Divides body into left and right parts.
Midsagittal Plane: Equal left and right sides.
Parasagittal Plane: Unequal left and right sides.
Oblique Plane: A combination of two or more planes.
Body Cavities
Dorsal Cavity: Contains the brain and spinal cord.
Ventral Cavity: Contains major organs (heart, lungs, abdominal organs). Divided into:
Thoracic Cavity: Contains heart and lungs.
Abdominal Cavity: Contains digestive organs, urinary organs, and reproductive organs.