Human Organism Study Guide PDF

PRELIMINARIES (THE HUMAN ORGANISM) Anatomy - the study of BODY STRUCTURES. Medical Approaches: 1. Systemic Anatomy - Study of the BODY SYSTEMS. 2. Regional Anatomy - Study of the BODY REGIONS. Examinations: 1. Surface Anatomy - Study...

PRELIMINARIES (THE HUMAN ORGANISM) Anatomy - the study of BODY STRUCTURES. Medical Approaches: 1. Systemic Anatomy - Study of the BODY SYSTEMS. 2. Regional Anatomy - Study of the BODY REGIONS. Examinations: 1. Surface Anatomy - Study of the EXTERNAL STRUCTURE. 2. Anatomical Imaging - Study of the INTERNAL STRUCTURES. Physiology - the study of BODY FUNCTIONS. 2 Goals a. Predict how the body reacts or responds to stimuli. b. Understand how the body maintains homeostasis. STRUCTURAL AND FUNCTIONAL BODY LEVELS 1. Chemical - interactions of atoms and molecules. 2. Cell - combine to form organelles, carrying out the work of the cell. 3. Tissue - combined cells that perform common structure and function. 4. Organ - 2 or more tissues to perform a specific function. 5. Organ System - 11 organs in the human body. 6. Organism - a living thing that's considered as a whole. BODY SYSTEMS Infrastructure (SMNCI) - Skeletal, Muscular, Nervous, Cardiovascular, Integumentary Energy (ELU) - Endocrine, Lymphatic, Urinary Regulatory (RD) - Respiratory, Digestive Reproductive (Rep) - Males and Females 6 ESSENTIAL CHARACTERISTICS OF LIFE 1. Organization - interrelationships to perform specific functions. 2. Metabolism - uses energy to perform vital functions. 3. Responsiveness - the ability to sense changes inside/outside the environment. 4. Growth - increase in size or number. 5. Development - changes that involve differentiation. 6. Reproduction - formation of new cells. FEEDBACK MECHANISMS A. Negative Feedback Mechanism - “To decrease” - Deviation from the set point is made smaller.  - Tries to fix a problem and bring things back to normal. Examples: 1. Body Temperature Regulation: ★ When body temperature rises, sweating is activated to cool the body down. Conversely, if body temperature drops, shivering generates heat to raise the temperature back to its set point. 2. Blood Glucose Regulation: ★ After eating, blood glucose levels rise, triggering the pancreas to release insulin, which helps lower blood glucose levels. As glucose levels decrease, insulin secretion slows down. 3. Thirst Mechanism: ★ As fluid levels decrease in the body, the sensation of thirst arises, prompting you to drink and restore balance. 4. Hormonal Regulation (e.g., Thyroid Hormones): ★ When levels of thyroid hormones are high, the hypothalamus reduces the release of TRH (thyrotropin-releasing hormone), which decreases TSH (thyroid-stimulating hormone) production and subsequently lowers thyroid hormone levels. B. Positive Feedback Mechanism - "To increase" - Deviation from the set point is made bigger. - Makes things happen faster and stronger until they reach a big goal. Examples: 1. Childbirth (Parturition): ★ During labor, the release of oxytocin increases uterine contractions, which stimulates further release of oxytocin until delivery occurs. 2. Blood Clotting: ★ When a blood vessel is damaged, platelets adhere to the site and release chemicals that attract more platelets, amplifying the response and forming a clot. 3. Lactation: ★ A baby suckling at the breast stimulates the release of prolactin and oxytocin, which promotes milk production and ejection, encouraging continued suckling. 4. Ripening of Fruit: ★ Certain fruits release ethylene gas as they ripen. This gas promotes more ethylene production in surrounding fruits, causing them to ripen faster. COMPONENTS: 1. Receptor: stimuli detector (monitors values) 2. Control Center: determines the set point of values. 3. Effector: change of value directed by the control center. BODY POSITIONS/RELATIVE POSITIONS 1. Supine - lying face UPWARD 2. Prone - lying face DOWNWARD 3. Anatomical Position - lying UPRIGHT 2 MAJOR REGIONS OF THE BODY 1. AXIAL - (Central) Trunk 2. APPENDICULAR - Limbs BODY PLANES 1. Saggital - “Flight of an Arrow” - Separates the left and right halves. 2. Median - A TYPE OF SAGITTAL PLANE that passes through the midline, cutting the halves in 2 EQUAL PARTS 3. Transverse - A horizontal cut of the body divides the superior and inferior portions. 4. Frontal  - Also known as the CORONAL - Divides the anterior and posterior portions. MEMBRANES OF THE BODY 1. Mucous Membranes (Mucosae): Location: Line cavities and tubes that OPEN TO THE OUTSIDE OF THE BODY (e.g., respiratory, digestive, urinary, and reproductive tracts). Function: Secrete mucus, which lubricates and protects the tissues. Examples: Lining of the mouth, nasal passages, and intestines. 2. Serous Membranes (Serosae): Location: Line body cavities that do NOT OPEN TO THE OUTSIDE and cover organs within these cavities. Function: Secrete serous fluid, which reduces friction between organs and the body wall. Examples: Pleura (lungs), pericardium (heart), and peritoneum (abdominal organs). 3. Cutaneous Membrane: Location: The SKIN covering the body’s exterior. Function: Protects underlying tissues from pathogens, dehydration, and injury. Example: The skin is a complex organ that acts as a barrier and regulates temperature. 4. Synovial Membranes: Location: Line the cavities of freely movable JOINTS (e.g., knee, elbow).  Function: Secrete synovial fluid, which lubricates and nourishes the cartilage in the joints. Examples: Knee, elbow, and shoulder joints. COMPONENTS for SEROUS: a. Visceral - Internal organ b. Parietal - Wall outside the organ ★ MESENTERIES - 2 layers of peritoneum FUSED - Connect the visceral to some abdominopelvic organs to the parietal. ★ RETROPERITONEAL - Abdominopelvic organs that are attached to the body wall. - DO NOT HAVE MESENTERIES. (TISSUES) - It refers to the group of specialized cells and extracellular substances surrounding them. - Cells that share COMMON STRUCTURE AND FUNCTION. - EPITHELIAL, CONNECTIVE, MUSCLE, NERVOUS. HISTOLOGY - the study or scientific discipline of tissues. 1. EPITHELIAL TISSUE (simple, pseudostratified, stratified, transitional, glandular) 1. Simple Squamous Epithelium Structure: One layer of flat, thin cells. Function: Allows materials like gases and fluids to pass through quickly. Location: Found in places where fast exchange happens, like the air sacs in lungs (alveoli) and blood vessels. 2. Simple Cuboidal Epithelium Structure: One layer of cube-shaped cells. Function: Absorbs or secretes substances, depending on the organ. Location: Found in glands and kidney tubules. 3. Simple Columnar Epithelium Structure: One layer of tall, column-like cells. Function: Absorbs nutrients and secretes mucus or enzymes. Location: Lines most of the digestive tract, like the stomach and intestines (ciliated and non-ciliated)  4. Pseudostratified Columnar Epithelium Structure: Appears to be layered, but all cells touch the base. Usually has tiny hair-like structures (cilia). Function: Secretes mucus and moves particles (like dust) out of the airways. Location: Found in the respiratory tract (trachea). 5. Stratified Squamous Epithelium Structure: Multiple layers of flat cells. Function: Protects against abrasion, drying out, and infection. Location: Found in the skin, mouth, and esophagus. 6. Stratified Cuboidal Epithelium Structure: Multiple layers of cube-shaped cells. Function: Protects and secretes. Location: Found in sweat glands, salivary glands, and mammary glands. 7. Stratified Columnar Epithelium Structure: Multiple layers of tall, column-like cells. Function: Provides protection and secretion. Location: Rare, but found in the male urethra and some large ducts. 8. Transitional Epithelium Structure: Layers of cells that can change shape from round to flat. Function: Allows stretching and shrinking. Location: Found in the bladder, stretching as it fills. 2. CONNECTIVE TISSUE (connective tissue proper, supporting CT, fluid CT) a. Connective Tissue Proper 1. Areolar Connective Tissue (mostly collagen, few elastic fibers) Structure: A loose, gel-like matrix with collagen and elastic fibers. It contains various cells, including fibroblasts (which produce fibers), macrophages (immune cells), and lymphocytes. Function: Provides cushioning, supports organs, binds tissues, and acts as a reservoir for water and salts. It also helps in defense against infection by housing immune cells. Location: Found beneath the skin (in the subcutaneous layer), around blood vessels, nerves, and organs. It acts as a filler between tissues. 2. Adipose Tissue (Fat Tissue - adipocytes)  Structure: Consists of adipocytes (fat cells) that store fat droplets in a sparse extracellular matrix. These cells are packed closely together and appear round and full. Function: Stores energy in the form of fat, provides insulation to help regulate body temperature, and cushions organs against mechanical injury. Location: Found under the skin (subcutaneous fat), around internal organs (visceral fat), in bone marrow, and areas like the breasts and hips. 3. Reticular Connective Tissue (reticular fibers) Structure: A network of thin, branching reticular fibers made of collagen arranged irregularly. It provides a supportive framework for certain organs. The tissue also contains fibroblasts and white blood cells. Function: Forms a soft, supportive skeleton (stroma) that supports other cells, particularly in immune and blood-forming tissues. Location: Found in lymphoid organs, such as the lymph nodes, spleen, and bone marrow, where it supports immune cells and blood cell development. b. Supporting Connective Tissue 1. Cartilage Structure: Flexible but firm matrix of collagen, elastic fibers, and a gel-like substance. The cells, called chondrocytes, are found in small spaces called lacunae. Cartilage lacks blood vessels (avascular), so it heals slowly. TYPES OF CARTILAGE: ○ Hyaline Cartilage Function: Provides smooth surfaces for joint movement, supports soft tissues, and allows the growth of long bones. Location: Found at the ends of long bones (articular cartilage), nose, trachea, and larynx, and as the fetal skeleton. ○ Elastic Cartilage Function: Provides flexibility and maintains the shape of certain structures. Location: Found in the ear (external ear), epiglottis, and parts of the larynx. ○ Fibrocartilage Function: Provides tough, strong support and withstands compression. Location: Found in intervertebral discs, the menisci of the knee, and the pubic symphysis. 2. Bone (Osseous Tissue) Bone tissue has a hard, mineralized matrix made up of: - Collagen fibers: Provide flexibility and tensile strength, preventing bones from being brittle. - Minerals: Mainly calcium and phosphate, which make the bone rigid and strong. - Cells (osteoblasts, osteocytes, osteoclasts)  TYPES OF BONES: ○ Compact Bone (Cortical Bone): Structure: Dense and solid. It consists of tightly packed osteons (Haversian systems), which are cylindrical structures made up of concentric layers (lamellae) of bone tissue around a central canal (Haversian canal) that contains blood vessels and nerves. Function: Provides strength and support for weight-bearing and protection. Location: Found on the outer layer of bones, especially in long bones (like the femur and humerus). ○ Spongy Bone (Cancellous or Trabecular Bone): Structure: Porous and lightweight, with a honeycomb-like structure made of thin, branching plates called trabeculae. It contains red or yellow bone marrow in the spaces between the trabeculae. Function: Supports and protects bone marrow and helps reduce the weight of bones while maintaining strength. Location: Found inside bones, especially at the ends of long bones (epiphyses) and in flat bones (like the pelvis, ribs, and skull). c. Fluid Connective Tissue 1. Blood Structure: ○ The matrix of blood is a fluid called plasma, which is mostly water but also contains proteins, nutrients, gases (like oxygen and carbon dioxide), hormones, and waste products. Cells in blood: 1. Red blood cells (erythrocytes): These cells carry oxygen from the lungs to tissues and bring carbon dioxide back to the lungs for exhalation. 2. White blood cells (leukocytes) are involved in immune defense, protecting the body from infections and foreign invaders. There are different types of white blood cells, including neutrophils, lymphocytes, and monocytes. 3. Platelets (thrombocytes): These small cell fragments are involved in clotting and help stop bleeding by forming a plug at injury sites. Function: ○ Transportation: Blood transports oxygen, carbon dioxide, nutrients, hormones, and waste products to and from cells. ○ Protection: White blood cells protect the body from infections, while platelets help in blood clotting. ○ Regulation: Blood helps regulate body temperature, pH levels, and the balance of fluids and electrolytes. Location: Blood circulates in blood vessels (arteries, veins, and capillaries) and through the heart.  3. MUSCLE TISSUE a. Skeletal Muscle Structure: ○ Skeletal muscle fibers are long, cylindrical, and multinucleated. They appear striated (striped) under a microscope due to the organized arrangement of contractile proteins (actin and myosin). ○ Skeletal muscle is voluntary, meaning you control its movement consciously. Function: ○ Responsible for voluntary movements such as walking, running, lifting objects, and facial expressions. ○ Also maintains posture and stabilizes joints. ○ Contributes to heat production during contraction. Location: ○ Attached to bones via tendons, skeletal muscles are found throughout the body, including muscles in the arms, legs, chest, back, and face. b. Cardiac Muscle Structure: ○ Cardiac muscle fibers are short, branched, and uninucleated (have one nucleus per cell). They also appear striated due to their organized protein fibers. ○ Cardiac muscle cells are connected by specialized junctions called intercalated discs, which help coordinate contractions and allow the heart to function as a unit. ○ Cardiac muscle is involuntary, meaning it contracts without conscious control. Function: ○ Responsible for pumping blood throughout the body by contracting and relaxing rhythmically. ○ Works continuously to maintain the heartbeat. Location: ○ Found only in the heart, specifically in the walls of the heart chambers (the myocardium). c. Smooth Muscle Structure: ○ Smooth muscle fibers are spindle-shaped, uninucleated, and non-striated (lacking visible stripes). They have a more uniform, smooth appearance under a microscope. ○ Smooth muscle is involuntary and works without conscious control. Function: ○ Smooth muscle contracts to move substances through hollow organs and structures, such as moving food through the digestive tract (peristalsis), controlling blood vessel diameter, and regulating airflow in the respiratory system. ○ It controls involuntary processes like digestion, blood flow, and childbirth (in the uterus). Location:  ○ Found in the walls of hollow organs, such as the stomach, intestines, bladder, blood vessels, airways, and uterus. 4. NERVOUS TISSUE a. Neurons: The primary cells of nervous tissue that transmit electrical impulses. They consist of a cell body, dendrites, and an axon. b. Neuroglia (Glial Cells): Supporting cells that protect, nourish, and insulate neurons. Types include astrocytes, oligodendrocytes, Schwann cells, and microglia. - Functions: Nervous tissue enables sensory input, integration of information, motor output, and rapid communication across the body, helping regulate and control bodily functions. - Location: Found in the body's brain, spinal cord, and peripheral nerves.