Introduction to the Human Body PDF

Introduction to the Human Body Natalie Duffy, MSPA, PA-C Summer 2024 Learning Objectives Descriptive Anatomical Terms Basic Structures of Skin Basic Structures of Bone Basic Structures of Muscle Basic Structures of Joints Describe the basic structures and...

Introduction to the Human Body Natalie Duffy, MSPA, PA-C Summer 2024 Learning Objectives Descriptive Anatomical Terms Basic Structures of Skin Basic Structures of Bone Basic Structures of Muscle Basic Structures of Joints Describe the basic structures and function of a ligament Describe the basic structures and function of a bursa Basic Structures of Blood Vessels Basic Structures of the Lymphatic System Basic Structures of the Nervous System (Refer to syllabus for more detailed list) Terminology Anatomical descriptions are based on a person being in the anatomical position: Standing erect and facing forward Arms hanging at the sides with palms facing forward Legs placed together with feet facing forward Body Planes Sagittal Plane- vertical plane that divides the body into equal right and left halves Frontal (coronal) Plane- vertical plane that divides the body into anterior and posterior portions Transverse (axial) Plane- a horizontal plane that divides the body into superior and inferior portions  1 2 3 Term Meaning Example Anterior (ventral) Near the front The nose is anterior to the ear Posterior (dorsal) Near the back The shoulder bladers are posterior to the ribs Superior (cranial) Upward, or near the head The heart is superior to the stomach Inferior (caudal) Downward, or near the feet The chest is inferior to the neck Medial Toward the midline The big toe is medial to the 5th toe Lateral Farther from the midline The thumb is on the lateral side of the hand Proximal Near a reference point, closer to the trunk or The hip is proximal to the knee point of origin Distal Away from a reference point, further from trunk The wrist is distal to the elbow or point of origin Superficial Closer to the surface Skin is superficial to the muscle Deep Further from the surgace The lungs are deep to the ribs Terms of relationship Terms of relationship Example: the nose is medial to the ear. The nose is also anterior to the ear. Practice Question Which of the following would describe the relationship between a patient’s foot and leg while in the anatomical position? A. The foot is distal to the leg B. The foot is proximal to the leg C. The foot is medial to the leg D. The foot is lateral to the leg Movements Body movements usually occur at the joints where two or more bones or cartilages articulate with one another. 8  Movement Matching Flexion The movement that increases the distance between two When there is a movement of a limb away from the midline, or Extension medianAbduction Extension bones or parts of the body. Example: straightening the plane of the body. Example: raising the arm or knee or elbow fanning the fingers. Abduction Adduction The combination of flexion, Rotation A movement of a bone around its longitudinal axis, very extension, abduction, and adduction movements, where Circumduction commonRotation for ball-and-socket joints. Example: shaking the Circumduction the proximal end of the limb is stationary, and its distal end head in a “no” gesture. moves in a circle. Example: doing big arm circles. This movement decreases the When there is a movement of a angle of the joint and brings limb towards the midline, just two bonesFlexion closer together. Adduction like “adding” a body part. Example: bending the elbow or Example: lowering down a bending forward raised arm.  Movement Matching Protrusion Retrusion A rotational movement of To thrust a body part out Supination from its anatomical Protrusion position. Example: sticking the forearm that results in the palmPronation facing posteriorly The movement of turning Eversion out. Example: turning out (when in the anatomic the sole of the foot. Pronation out the jaw position) or down. Eversion Describes a rotational To return a body part from movement of the forearm Inversion thrusting out back to its Retrusion that results in the palm The movement of turning in. Inversion facingSupination anatomical position. Example: turning in the sole anteriorly (when in Example: returning the jaw of the foot. the anatomic position) or to its anatomical position. up. Skin Largest organ in the body accounting for 15% to 20% of the total body mass Functions: Protection- against abrasions and in immune response; prevention of dehydration Temperature Regulation- fat storage and activation of sweat glands Sensations- to touch, pain, and temperature Endocrine Regulation- secretion of hormones, synthesis and storage of vitamin D Exocrine Secretions- secretion of sweat and oily sebum from sebaceous glands Skin Layers Epidermis- outer protective layer consisting of keratinized stratified squamous epithelium Dermis- dense connective tissue layer; gives skin most of its thickness and support Subcutaneous tissue- deepest layer that rests just above the deep fascia Skin Appendages of the skin: Nails- horny covering on the upper surface of the tip of the fingers and toes Hair follicle- the sheath of cells and connective tissue which surrounds the root of a hair Sebaceous gland- secretes lubricating oily matter (sebum) into the hair follicles to lubricate the skin and hair Sweat gland- secretes sweat and situated in the dermis 13 Clinical Application: Burns Burns classified as follows: First degree- burn damage that is limited to the superficial layers of the epidermis Second degree- burn damage that includes all the epidermis and extends into the superficial dermis Third degree- burn damage that includes all the epidermis and dermis and may involve subcutaneous tissue and Epidermis Dermis Subcutaneous underlying deep fascia and tissue muscle 14 Skeletal System Divided into 2 descriptive regions Axial Skeleton Includes the bones of the skull, vertebral column (spine), ribs and sternum These form the “axis” or central line of the body (80 bones) Appendicular Skeleton Includes the bones of the limbs, pectoral and pelvic girdles which attach the limbs to the body’s axis (134 bones) Function of the skeletal system is to support, protect vital organs, movement, storage of calcium and other salts/growth factors, a source of blood cells (bone marrow). Skeletal System Skeletal System Bones can be classified in 5 shapes 1. Long (humerus, femur) 2. Short (carpals, cuneiforms) 3. Flat (parietal bone, sternum) 4. Irregular (vertebra) 5. Sesamoid (Patella) Skeletal System Epiphysial plate Two (2) types of bone composition: 1. Compact- relatively solid mass of bone, commonly seen as a superficial layer of bone, provides strength 2. Spongy- a less dense trabeculated network of bone spicules making up the substance of most bones and surrounding an inner marrow cavity Long bones have the following descriptive regions: 1. Epiphysis- the ends of long bones 2. Epiphysial plate- the site of growth in length; contains cartilage in actively growing bones 3. Metaphysis- the site where the bone’s shaft joins the epiphysis and the epiphysial plate 4. Diaphysis- the shaft of a long bone, the primary ossification center and the site where growth in width occurs 18 Skeletal System  Skeletal System Blood Supply: Nutrient arteries- supply the compact and spongy bone and the bone marrow Metaphysial and epiphysial arteries- arising from articular branches supplying the joint Periosteal arteries- supply the compact bone Markings on the Bones Condyle A rounded articular surface covered with hyaline cartilage Crest A ridge (narrow or wide) of bone Epicondyle A prominent ridge or eminence superior to a condyle Facet A flat, smooth articular surface, usually covered with hyaline cartilage Fissure A very narrow “slitlike” opening in a bone Foramen A round or oval “hole” in the bone for passage of another structure Fossa A “cuplike” depression in a bone, usually for articulation with another bone Groove A furrow in the bone (long narrow trench) Line A fine linear ridge of bone, but less prominent than a crest Malleolus A rounded eminence Meatus A passageway or canal in a bone Process A bony prominence that may be sharp or blunt Protuberance A protruding eminence on an otherwise smooth surface Ramus A thin part of a bone that joins a thicker process of the same bone Spine A sharp process projecting from a bone Trochanter Large, blunt process for muscle tendon or ligament attachment Tubercle A small, elevated process Tuberosity A large, rounded eminence that may be coarse or rough Greater trochanter Ischial tuberosity Types of Joints Joints are the sites of union or articulation of two or more bones or cartilages 3 types Fibrous- bones joined by fibrous connective tissue Cartilaginous- bones joined by cartilage and fibrous tissue Synovial- the most common type of joint; bones are joined by a joint cavity filled with a small amount of synovial fluid and surrounded by a capsule ▪ Further divided into 6 types Types of Fibrous joints include sutures (flat bones of the skull), syndesmoses (two bones connected by a Fibrous Joints fibrous membrane), and gomphoses (teeth fitting into fibrous tissue-lined sockets).  Cartilaginous joints include primary joints between surfaces lined by Types of hyaline cartilage (epiphysial plate connecting the diaphysis with the epiphysis) Secondary joints between hyaline-lined articular surfaces and an Cartilaginous Joints intervening fibrocartilaginous disc. Primary joints allow for growth and some bending, whereas secondary joints allow for strength and some flexibility. Types of Synovial Uniaxial; for rotation Multiaxial; for flexion, extension, abduction, Joints adduction, circumduction, and mediolateral rotation Uniaxial; Biaxial; for flexion, for flexion and extension, abduction, extension adduction, and circumduction Biaxial; For flexion, extension, abduction, Joints that only allow adduction and circumduction simple gliding movements Muscular System Muscle cells produce contractions that result in movement, maintenance of posture, changes in shape, or the propulsion of fluids through hollow tissues or organs. 3 different types of muscle: Skeletal- striated muscle fibers that are attached to bone and are responsible for movements of the skeleton ▪ Possesses an origin and an insertion Cardiac- striated muscle fibers that make up the walls of the heart and proximal portion of the great veins where they enter the heart Smooth- non-striated muscle fibers that line various organ systems, attach to hair follicles, and line the walls of most blood vessels Muscular System  Ligament- fibrous connective tissue that connects bones to bones and serve to hold structures together Skeletal and Tendon- fibrous connective tissue that attach Muscular System muscles to bone or other body structures. Bursa- a fluid-filled sac or saclike cavity, especially one countering friction at a joint. 30 Brain break! Everyone stand up for a game of "Simon Says"  Pulse Points Cardiovascular System Consists of: 1. The heart 2. The vessels Arteries carry blood away from the heart High pressure system, "supplies" Veins carry blood back to the heart Low pressure system, "reservoir" Valves and skeletal muscle help to “pump” blood back to the heart Pulse- can be taken by compressing a medium to large sized artery, where it lies near the body’s surface, against a hard underlying surface (usually a bone). Cardiovascular System Lymphatic System Functions to: Protect the body against infection by activating defense mechanisms of the immune system Collect tissue fluids, solutes, hormones, and plasma proteins and return them to the circulatory system Absorb fat (chylomicrons) from the small intestine  Lymphatic System Components of the Lymphatic System: Lymph- a colorless, watery fluid that contains lymphocytes which supply tissues through the lymphatic system Lymphocytes- the cellular components of lymph, including T cells and B cells Lymph Vessels- an extensive network of vessels and capillaries in the peripheral tissues that transport lymph and lymphocytes Lymphoid Organs- collections of lymphoid tissues, including lymph nodes, aggregates of lymphoid tissue along the respiratory and GI tract, tonsils, thymus, spleen, and bone marrow. Lymph Nodes- “filters” the lymph as it moves toward the venous system They can also initiate the body’s immune response Lymphatic System Immune Response- a response initiated to neutralize a pathogen such as a foreign microorganism, virus-infected cell, or cancer cell. The body has 3 major responses to protect against foreign invaders 1. Non-specific Barriers- 1st line of defense; skin and mucous membranes 2. Innate Immunity- 2nd line of defense; composed of a variety of cells and anti-microbial secretions 3. Adaptive Immunity- 3rd line of defense; characterized by specific pathogen recognition, immunologic memory, amplification of immune responses, and rapid response against pathogens that re-invade the body Lymphatic drainage Body is about 60% fluid by weight; 40% in intracellular fluid (ICF) and 20% in extracellular fluid (ECF) Lymphatics are essential for returning ECF, solutes, and protein back to the bloodstream, thus helping to maintain normal blood volume Lymphatics also distribute various hormones, nutrients, and waste products from the ECF to the bloodstream The majority of lymph (75-80%) ultimately collects in the thoracic duct (located on left) o A much smaller right lymphatic duct drains the right upper quadrant of the body lymphatics to a similar site on the right side Respiratory System Provides oxygen to the body for its metabolic needs and eliminates carbon dioxide Respiratory System Contains: Nose and paranasal sinuses. Pharynx and its subdivisions (nasopharynx, oropharynx, and laryngopharynx). Larynx, continuous with the trachea inferiorly. Trachea. Bronchi, bronchioles, alveolar ducts/sacs, and alveoli Lungs (a right lung and a left lung) Performs 5 basic functions: Filters and humidifies the air and moves it in and out of the lungs Provides a large surface area for gas exchange with the blood Helps to regulate the pH of body fluids Participates in vocalization Assists the olfactory system with the detection of smells  Nervous System The nervous system integrates and regulates many body activities Central nervous system (CNS): includes the brain and spinal cord. Peripheral nervous system (PNS): includes the somatic, autonomic, and enteric nerves in the periphery and outside the CNS. Two structural divisions: Central nervous system (CNS): includes the brain and spinal cord. Peripheral nervous system (PNS): includes the somatic, autonomic, and enteric nerves in the periphery and outside the CNS.  Nervous system Central nervous Peripheral nervous system (CNS): brain and system (PNS): cranial spinal cord nerves, spinal nerves Somatic (voluntary) Autonomic (involuntary) Sympathetic Parasympathetic  Nerve cells are called neurons Information comes to the neuron through tree-like Neurons process called axons, which terminate on the neuron at the synapse. Synapses can occur on neuronal processes called dendrites or on the neuronal body called a soma. Neurons Neurons convey efferent (motor or input) information via action potentials that course along a single axon arising from the soma and then synapses on a target (another neuron or target cell such as muscle cells) All neurons can be classified into one of three functional types o Sensory neurons: they convey afferent impulses from peripheral receptors to the CNS ▪ Eg. When you touch a hot stove, sensory neurons send afferent signals to the CNS signaling HOT! OUCH! o Motor neurons: they convey efferent impulses from the CNS to target (effector) cells. ▪ Eg. Motor neurons send efferent impulses to muscle cells signaling MOVE HAND! o Interneurons: they convey impulses between sensory and motor neurons in the CNS, thus forming integrated networks between cells; interneurons probably account for more than 99% of all neurons in the body. Neurons Glial cells Astrocytes: these are the most numerous of the glial cells; provide physical and metabolic support for CNS neurons, can become reactive during CNS injury, release growth factors and other bioactive molecules, and contribute to the formation of the blood- brain barrier. Oligodendrocytes: these are smaller glial cells; responsible for the formation and maintenance of myelin in the CNS. Microglia: these are smallest and rarest of CNS glia, although more numerous than neurons in CNS; these phagocytic cells participate in inflammatory reactions, remodel and remove synapses, and respond to injury. Ependymal cells: these cells line the ventricles of the brain and the central canal of the spinal cord, which contains cerebrospinal fluid. Schwann cells: these are the glial cells of the PNS; surround all axons (myelinating many of them) and provide trophic support, facilitate regrowth of PNS axons, and clean away cellular debris.  Glial cells Glial Cells Functions Astrocytes Provide physical and metabolic support for CNS neurons, can become reactive during CNS injury, release growth factors, contribute to the formation of the blood-brain barrier Oligodendrocytes Responsible for the formation and maintenance of myelin in the CNS Microglia Phagocytic cells participate in the inflammatory reactions, remodel and remove synapses, and respond to injury Ependymal Cells Line the ventricles of the brain and central canal of the spinal cord, which contains cerebrospinal fluid Schwann Cells Glial cells of the PNS Surround all axons and provide support, facilitate regrowth of PNS axon, and clean away cellular debris  Nervous system Central nervous Peripheral nervous system (CNS): brain system (PNS): cranial and spinal cord nerves, spinal nerves Peripheral Nervous System (PNS) Network of nerves that work to carry messages to and from the brain and spinal cord (CNS) Peripheral Nerves include the 12 pairs of cranial nerves arising from the brain or brainstem and the 31 pairs of spinal nerves arising from the spinal cord. Cranial nerves 12 pairs which arise from the brain They are identified by both their name and Roman numerals I to XII. Cranial nerves possess multiple functional components like motor, sensory, and both. Cranial Nerves Cranial Nerves Mnemonic Peripheral Nervous System Spinal Nerves 31 pairs of spinal nerves which then form 2 major branches Posterior (dorsal) ramus- a small ramus that courses dorsally to the back; it conveys motor and sensory information to and from the skin and intrinsic back skeletal muscles Anterior (ventral) ramus- a much larger ramus that courses laterally and ventrally; it innervates all the remaining skin and skeletal muscles of the neck, limbs, and trunk Peripheral Nervous System Posterior Spinal Nerves Anterior Peripheral Nervous System 31 pairs of Spinal Nerves 8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal  Nervous system Central nervous Peripheral nervous system (CNS): brain and system (PNS): cranial spinal cord nerves, spinal nerves Somatic (voluntary) Autonomic (involuntary) Somatic Nervous System Sensory and motor fibers to skin, skeletal muscle, and joints It is a one-neuron motor system. The motor (efferent) neuron is in the CNS, and an axon projects to a peripheral target (e.g., skeletal muscle). The sensory (afferent) neuron resides in a peripheral ganglion called a spinal ganglion and conveys sensory information from the skin, muscle, or joint to the CNS (in this case the spinal cord). Dermatomes An area of skin innervated by a specific spinal root nerve. 30 dermatomes in total (there is not one associated with the 1st cervical spinal nerve) Autonomic Nervous System Sensory and motor fibers to smooth muscle (viscera, vasculature), cardiac muscle, and glands It is a two-neuron motor system; the first neuron resides in the CNS and the second neuron in a peripheral autonomic ganglion. A ganglion is a group of cell bodies located in the peripheral nervous system The axon of the first neuron is termed preganglionic and of the second neuron, postganglionic. The postganglionic neuron then sends its axon to the target (smooth muscle, cardiac muscle, and glands)  Nervous system Central nervous Peripheral nervous system (CNS): brain and system (PNS): cranial spinal cord nerves, spinal nerves Somatic (voluntary) Autonomic (involuntary) Sympathetic Parasympathetic Autonomic nervous system Divided into sympathetic and parasympathetic divisions These 2 systems balance each other out. The sympathetic nerves control the body’s “fight, flight or fright” response The parasympathetic nerves help to control your body’s response during times of rest: "rest and digest" Sympathetic Nervous System Sympathetic trunk Paravertebral ganglia White communicating ramus Grey communicating ramus  Grey ramus communicans Unmyelinated nerves (grey) White ramus communicans Return FROM sympathetic Pre-ganglionic branch ganglion Myelinated axons (hence: Rejoin spinal nerve, go to target white) organ Going TO sympathetic ganglion Sympathetic nervous system Parasympathetic Nervous System Cranial parasympathetic ganglia Parasympathetic nervous system Questions? Comments? Concerns? Quiz: Introduction to the Human Body & Introduction to Radiology Monday 7/8/2024 at 9:00 AM in Aud B