Anatomy Basics PDF Notes

Overview • Anatomy: the study of bodily structures – Gross Anatomy = macroscopic, big picture – Microanatomy = microscopic; histology (tissues) and cytology (cells) • Physiology: the study of bodily functions • Structurally, organisms are made up of organ systems, which are made up of organs, whi...

Overview • Anatomy: the study of bodily structures – Gross Anatomy = macroscopic, big picture – Microanatomy = microscopic; histology (tissues) and cytology (cells) • Physiology: the study of bodily functions • Structurally, organisms are made up of organ systems, which are made up of organs, which are made up of tissues, which are made up of cells. – Functionally, a dynamic equilibrium is maintained from the system level, all the way down to the cellular level – Nothing works in isolation – even the organ systems all work together! Skeletal system • Main function: support, protection for internal organs, and aid in movement • Key structures: bones, tendons, ligaments, and cartilage Muscular system • Main function: movement and stabilization • Key structures: skeletal, smooth, and cardiac muscles Nervous system • Main function: collect, process and respond to sensory information; control voluntary and involuntary (reflex) actions • Key structures: brain, spinal cord, and all connected nerves and sensory organs – Key cells are called neurons Endocrine system • Main function: production and secretion of hormones for regulation of the body (growth, metabolism, and sexual development) • Key structures: Hypothalamus and glands (like pituitary, adrenal, thyroid) Cardiovascular system • Main function: gas exchange and nutrient transport to and from cells throughout the body • Key structures: Heart, blood vessels (like arteries, capillaries, and veins) and blood Respiratory system • Main function: gas exchange; taking in oxygen and getting rid of carbon dioxide • Key structures: Lungs, nose, mouth, trachea and diaphragm Digestive system • Main function: Break down of food and absorption of nutrients for the body • Key structures: Mouth, stomach, and intestines Urinary system • Main function: maintains water balance, gets rid of waste, regulates blood volume and pressure, and filters blood • Key structures: Kidneys and bladder Integumentary system • Main function: acts as a barrier to protect the body from the outside world, as well as regulates temperature and controls water loss • Key structures: Skin, hair, nails, and associated glands Immune and Lymphatic systems • Main function: defend, deflect and destroy infectious agents that make their way into the body • Key structures: Lymph nodes, blood vessels, thymus, bone marrow, and spleen Reproductive system • Main function: allows animals to reproduce (aka, make babies) by producing egg and sperm, hormones, and nurturing developing offspring. • Key (male) structures: • Key (female) structures: testes and penis vagina, uterus, and ovaries Anatomical Terminology • Anatomical position: where a person is standing up with feet slightly apart and arms at their sides – This standard position is used as a reference point when using directional terms • Note: Right and left are from his perspective Regional Terms • Axial: head, neck, and trunk – Think about what is off the main axis of the body • Appendicular: appendages (limbs) attached to the axis Directional Terms • Superior (cranial): toward the upper part; above – Ex. The chin is superior to the abdomen. • Inferior (caudal): away from the upper part, toward the lower part; below – Ex. The knees are inferior to the navel. Directional Terms • Anterior (ventral): toward or at the front of the body; in front of – Ex. The chin is anterior to the spine. • Posterior (dorsal): toward or at the back of the body; behind – Ex. The spine is posterior to the heart. Directional Terms • Medial: toward or at the midline of the body; on the inner side of – Ex. The heart is medial to the arm. • Lateral: away from the midline of the body; on the outer side of – Ex. The arms are lateral to the chest. • Intermediate: in between Directional Terms • Proximal: closer to the point where a limb attaches to the body trunk – Ex. The elbow is proximal to the wrist. • Distal: farther from the point where the limb attaches to the body trunk – Ex. The toes are distal to the knee. Directional Terms • Superficial (external): toward or at the body surface – Ex. The skin is superficial to the bones. • Deep (internal): away from the body surface – Ex. The heart is deep to the ribcage. Body Planes (Sections) To study the human body, it is often sectioned off along flat surfaces called planes. Below are the most frequently used. Body Planes (Sections) • Sagittal: a vertical plane that divides the body into left and right sections – If it goes directly through the midline, it is a midsagittal (median) plane – If it cuts off the midline, it is a parasagittal plane • Frontal (coronal): a vertical plane that divides the body into anterior (front) and posterior (behind) sections • Transverse (cross section): a horizontal plane that divides the body into superior (above) and inferior (below) sections Body Cavities Anatomists typically divide the body into two membrane-lined internal cavities that protect the organs within them, each having 2 major subdivisions. • Dorsal body cavity – Part of the axial portion of the body, encased in bony structures for protection – Houses the fragile nervous systems organs – Includes: • Cranial cavity: holds the brain (encased by the skull) • Vertebral (Spinal) cavity: holds the spinal cord within the bony vertebrae Body Cavities Anatomists typically divide the body into two membrane-lined internal cavities that protect the organs within them, each having 2 major subdivisions. • Ventral body cavity – Part of the axial portion of the body, less protected but allows more mobility – Houses the visceral organs – Includes: • Thoracic cavity: holds the heart and lungs (protected by ribs and chest muscles) – Pleural cavities: hold the lungs – Pericardial cavity (within the mediastinum): holds the heart, esophagus, and trachea • Abdominopelvic cavity: holds the abdomen and pelvis Body Cavities A bit more about the abdominopelvic cavity • Abdominopelvic cavity: holds the abdomen and pelvis – Abdominal cavity: holds the stomach, intestines, spleen, liver (as well as other organs) – Pelvic cavity: holds the bladder, some reproductive organs, and rectum (protected by the pelvis) Often divided into 4 quadrants Other Body Cavities • These other body cavities are much smaller and many have external openings. – Oral cavity: contains the mouth, including the teeth and tongue – Digestive cavity: connects the oral cavity all the way to the rectum – Nasal cavity: within and behind the nose – Orbital cavities: hold the eyes – Middle ear cavities: contain tiny bones medial to the eardrums – Synovial cavities: joint cavities Body Membranes • Body membranes line body cavities and cover the organs within them. – Cutaneous membrane: your skin, which covers your body’s surface • The only dry membrane! – Mucous membranes (Mucosae): line all body cavities that open to the outside of the body • Ex. Nasal cavity, mouth, etc. – Serous membrane (Serosa): lines ventral body cavities that are closed, as well as covering many organs • Parietal membrane: lines the body cavity • Visceral membrane: covers the internal organs • These serous membranes are separated by serous fluid – Meninges: the membrane that covers the brain and spinal cord in the dorsal body cavity