External Anatomy of Farm Animals PDF

Chapter 2. Anatomy & Physiology of Farm Animals: External Anatomy 2.1. Directional terms 2.2. Main body divisions 2.3 Integumentary System Objectives:  For overview of Anatomy & Physiology: 1. Define Anatomy & Physiology 2. Explain how anatomy and physiology are related.  Identify anatomica...

Chapter 2. Anatomy & Physiology of Farm Animals: External Anatomy 2.1. Directional terms 2.2. Main body divisions 2.3 Integumentary System Objectives:  For overview of Anatomy & Physiology: 1. Define Anatomy & Physiology 2. Explain how anatomy and physiology are related.  Identify anatomical parts of the animal as well as discuss its physiology.  Homeostasis: 1. Define homeostasis and explain its importance; 2. Define negative feedback and describe its role in maintaining homeostasis and normal body function.  The language of anatomy: 1. Describe the anatomical position verbally or demonstrate it; 2. Use proper anatomical terminology to describe body directions, surfaces and body planes;  An Overview of Anatomy & Physiology  Anatomy (Greek words tomy - to cut & ana – apart) -study of structure & shape of the body/ body parts & their relationship to one another.  Gross Anatomy (Macroscopic Anatomy) -study of macroscopic body structures.  Histology (Microscopic Anatomy ) -study of minute bodily structures with an aid of a magnifying lens or microscope. Basic approaches to the study of Anatomy A. Systemic anatomy – study of the body by systems. e.g. Integumentary system, Circulatory System, Nervous System B. Regional anatomy – study of the organization of the body by areas/ region; all systems are studied at the same time. C. Surface anatomy- uses superficial structures to locate deeper structures; anatomic imaging a noninvasive method for examining deep structures. Physiology  The study of how body and its parts work or function.  (physio = nature; ology = the study of) Major Goals of Physiology: 1) To understand & predict the body’s responses to stimuli, & 2) To understand how the body maintains conditions w/in a narrow range of values in the presence of a continually changing environment.  Physiology divided according to: 1) The organisms involved, e.g. Physiology, or 2) The levels of organization w/in a given organism, e.g., Cellular & Systemic Physiology  Relationship b/w Anatomy & Physiology  Anatomy & Physiology - always related i.e., body parts form a well organized unit; each part w/ specific task to do to make body operate as a whole. Characteristics of Life 1. Organization – condition in w/c all parts of an organism have specific relationships to each other;  Levels of Structural Organization 1.Chemical 2. Cellular Level – Molecules – level – associate in specific ways to form simplest level organelles, e.g. nucleus w/c Atom- minute make up Cells building blocks of matter; combines to form molecules. 3. Tissue Level – similar cells/ surrounding materials make up tissues 6. Organism Level 5. Organ - System Level 4. Organ Level 2. Metabolism – ability to use energy to perform vital functions. 3. Responsiveness/ Irritability – ability to sense changes in the environment & make the needed adjustments that help maintain life. 4. Growth – increase in size of all or part of an organism a) Hyperthrophy – increase in size of a cell / organ. b) Hyperplasia – increase in the number of cells 5. Development – includes the changes an organism undergoes through time. 6. Reproduction – formation of new cells or new organisms. Homeostasis  Body’s ability to maintain stable internal condition (dynamic state of equilibrium or balance).  Attained when body needs are adequately met & is functioning smoothly. Homeostatic Control Mechanisms  Communication w/in the body essential for homeostasis;  Accomplished by: a) Neural (electrical signals delivered by the nerves) & Hormonal Control Systems (blood-borne hormones) as info. carriers; Three Components: a. Receptor – type of sensor that monitors & responds to changes in the environment; - responds to changes, e.g., stimuli by sending information (input) to 2nd element (control center) - information flows from receptor to control center via afferent pathway. b. Control Center - determines the level (set point) at w/c a given variable is to be maintained; - analyzes the information it receives, & - determines appropriate response. c. Effector -provides means for control center’s response (output) to a given stimulus. - info flows from control center to effector via efferent pathway  (3) Input: 4) Output: Information sent Information sent along afferent along efferent pathway pathway to activate (2) Change detected by (5) Response of receptor effector feeds back to influence magnitude of (1) Stimulus: stimulus & returns Produces change in variable to variable homeostasis Negative Feedback Mechanisms - functions to maintain homeostasis; - any deviation from the set point is made smaller or is resisted; - do not prevent variation but maintain variation w/in normal range. e.g. maintenance of normal B.P. Terminology and the Body Plane  Body Positions  Anatomical position refers to a person standing erect with face directed forward, upper limbs hanging to the sides, & palms of the hands facing forward. A person is supine when lying face upward & prone when lying face downward.  Super Superior superior Proximal Posterior Infe (Dorsal) inferior Distal Inferior Proximal Distal Proximal Figure 1.7 Directional Terms All directional terms are in relation to a person in the anatomic position: a person standing erect with the face directed forward, the arms sides, and the palms of the hands facing forward.  position of the body can affect description of body parts relative to each other.  e.g. In anatomic position, the elbow is above the hand, but in supine or prone position, the elbow & hand are at the same level.  Directional Terms  Right & left are retained as directional terms in anatomic terminology.  Up is replaced by superior,  down by inferior,  front by anterior (means that which goes before, & ventral means belly)  back by posterior (that which follows, & dorsal means back).  Proximal - nearest,  Distal – distant; terms used to refer to linear structures, (e.g. limbs) in w/c one end is near some other structure & the other end is farther away. e.g. each limb is attached at its :  proximal end to the body &  distal end (hand) is farther away.  Medial - toward the midline;  Lateral - away from the midline. e.g.The nose is located in a medial position in the face, and the eyes are lateral to the nose.  Superficial -refers to a structure close to the surface of the body; e.g. The skin is superficial to muscle & bone.  Deep - toward the interior of the body. Table 1. DIRECTIONAL TERMS FOR HUMANS Terms Etymology Definition Example Right Toward the The right ear body's right side Left Toward the The left ear body's left side Inferior Lower Below The nose is inferior to the forehead Superior Higher Above The mouth is superior to the chin Table 1. DIRECTIONAL TERMS (cont.) Terms Etymology Definition Example Anterior To go Toward the The teeth before front of the are anterior body to the throat Posterior Posterus, Toward the The brain is following back of the posterior to body the eyes Dorsal Dorsum, Toward the The spine is back back dorsal to the (synonymous breastbone with posterior) Table 1. DIRECTIONAL TERMS (cont) Terms Etymology Definition Example Ventral Venter, belly Toward the The navel is belly ventral to the (synonymous spine. with anterior) Proximal Proximus, Closer to a The nearest point of phalanges is attachment proximal to the wrist. Distal di + sto, to Farther from a The knee is be distant point of distal to the attachment hip. Table 1. DIRECTIONAL TERMS (cont) Terms Etymology Definition Example Lateral Latus, side Away from The nipple is the midline lateral to the of the body breastbone Medial Medialis, Toward the The bridge of middle middle or the nose is midline of medial to the the body eye. Superficial Superficialis, Toward or on The skin is surface the surface superficial to muscle Table 1. DIRECTIONAL TERMS (cont.) Terms Etymology Definition Example Deep Deop, deep Away from The lungs the surface, are deep to internal the ribs.  Body Parts and Regions A. Upper limb : arm, forearm, wrist & hand. a.1 Arm - shoulder to the elbow, a.2 Forearm - elbow to the wrist. B. Lower Limb: thigh, leg, ankle, & foot. b.1 Thigh - hip to knee b.2 Leg - knee to ankle C. The Central Region of the Body consists of the head, neck, & trunk. c.1 Trunk divided into: c.1.1 Thorax (chest), c.1.2 Abdomen (region b/w thorax & pelvis) c.1.3 Pelvis (inferior end of trunk associated w/ hips).  Frontal (forehead) Cephalic Orbital (eye) Otic (ear) (head) Nasal(nose) Buccal (cheek) Oral (mouth)—— Mental (chin) Cervical (neck) - Clavicular (collar bone) Pectoral (chest) Thoracic Axillary (arm pit) (thorax) Sternal (breastbone) Upper Mammary (breast) Brachial (arm) limb Antecubital (front of elbow) Trunk Abdominal (abdomen) Umbilical (navel) Antebrachial (forearm) Pelvic (pelvis) Inguinal (groin) Carpal (wrist) Pubic (genital) Palmar (palm) manual — Manual (hand) Digital (fingers) Coxal (hip) Femoral (thigh) Patellar (kneecap) Crural (leg) Lower — Lower limb limb Talus (ankle) Dorsum (top of foot) — Pedal (foot) Pedal Digital (toes) (a) (foot) Figure 1.8 Body Parts and Regions The anatomic and common (in parentheses) names are indicated for some parts and regions of the body. (a) Anterior view.  Cranial (skull) Occipital (base of skull) Nuchal (back of neck) Acromial (point of shoulder) Scapular (shoulder blade) Dorsal Vertebral (back) (spinal column) Olecranon (point of elbow) UPPER LIMB Lumbar (Loin) TRUNK - Sacral (between hips) Dorsum (back of hand) Gluteal(buttock) Perineal (perineum) Popliteal (hollow behind knee) Sural (calf) LOWER LIMB Plantar (sole) Calcaneal (heel) Figure 1.8 Body Parts and Regions (continued) Abdomen:  subdivided superficially into four quadrants by two imaginary lines—one horizontal & one vertical—that intersect at the navel.  Quadrants formed are: a) right upper quadrant b) left upper quadrant c) right lower quadrant & d) left lower quadrant Subdivisions of the Abdomen Lines are superimposed over internal organs to demonstrate the relationship of the organs to the subdivisions, (o) Abdominal quadrants consist of four subdivisions, Planes (imaginary flat surfaces)  Sagittal plane - runs vertically thru the body & separates it into right & left parts.  Median plane - sagittal plane that passes thru the midline of the body & divides it into equal right & left halves.  Transverse/ Horizontal plane -runs parallel to the surface of the ground & divides the body into superior & inferior parts.  Frontal /Coronal plane - runs vertically from right to left & divides the body into anterior & posterior parts.  Frontal section through the right hip Figure 1.10 Planes of Section of the Body Planes of section through the whole body are indicated by "glass" sheets. Actual sections through the head (viewed from the right), abdomen (inferior view), and hip (anterior view) are also shown.  Organs often sectioned to reveal their internal structure.  A cut thru the long axis of the organ is a Longitudinal Section.  A cut at a right angle to the long axis is a Transverse / Cross section.  If a cut is made across the long axis at other than a right angle, it is called an Oblique Section.  Intestine Transverse section Oblique section Figure 1.11 Planes of Section Through an Organ Planes of section through the small intestine are indicated by "glass" sheets. Although the small intestine is basically a tube, the sections appear quite different in shape.  Body Cavities  body contains many cavities.  Some such as the nasal cavity open to the outside of the body, and some do not. The trunk contains three large cavities that do not open to the outside of the body:  Three cavities: a) Thoracic cavity b) Abdominal Cavity, c) Pelvic cavity  Mediastinum (divides thoracic cavity) Thoracic cavity Diaphragm Abdominal Abdominopelvic cavity cavity Figure 1.12 Trunk Cavities (a) Anterior view showing the major trunk cavities. The diaphragm separates the thoracic cavity from the abdominal cavity. The mediastinum, w the heart, is a partition of organs dividing the thoracic cavity, (b) Sagittal section of the trunk cavities viewed from the left. The dashed line show between the abdominal and pelvic cavities. The mediastinum has been removed to show the thoracic cavity. a) Thoracic cavity - surrounded by the rib cage; separated from abdominal cavity by the muscular diaphragm.  divided into right & left parts by a median structure called the mediastinum.  Mediastinum - a partition containing the heart, thymus, trachea, esophagus & other structures.  The two lungs are located on either side of the mediastinum. b) Abdominal Cavity - bounded primarily by the abdominal muscles; contains the stomach, intestines, liver, spleen, pancreas & kidneys. c) Pelvic Cavity - a small space enclosed by the bones of the pelvis; contains the urinary bladder, part of the large intestine, & internal reproductive organs.  The abdominal & pelvic cavities are not physically separated & sometimes are called the abdominopelvic cavity  THE END Thank You for listening!!!