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Questions and Answers
Which body plane divides the body into equal right and left halves?
Which body plane divides the body into equal right and left halves?
The term 'proximal' means further from a reference point.
The term 'proximal' means further from a reference point.
False
The _______ is superficial to the muscle.
The _______ is superficial to the muscle.
skin
Match the directional movement with its description:
Match the directional movement with its description:
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What are the types of joints mentioned in the content?
What are the types of joints mentioned in the content?
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Define Ligament as mentioned in the text.
Define Ligament as mentioned in the text.
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Smooth muscle fibers line the walls of most blood vessels. Is this statement true?
Smooth muscle fibers line the walls of most blood vessels. Is this statement true?
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The structure that lines the ventricles of the brain and the central canal of the spinal cord is called ________ cells.
The structure that lines the ventricles of the brain and the central canal of the spinal cord is called ________ cells.
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Match the following bone markings with their descriptions:
Match the following bone markings with their descriptions:
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What is the function of astrocytes in the central nervous system?
What is the function of astrocytes in the central nervous system?
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What is the primary function of oligodendrocytes in the CNS?
What is the primary function of oligodendrocytes in the CNS?
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Which type of cells are responsible for phagocytosis and inflammatory reactions in the CNS?
Which type of cells are responsible for phagocytosis and inflammatory reactions in the CNS?
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Microglia participate in the inflammatory reactions, remodel and remove synapses, and respond to ____________.
Microglia participate in the inflammatory reactions, remodel and remove synapses, and respond to ____________.
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Match the following divisions with their functions:
Match the following divisions with their functions:
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Study Notes
Introduction to the Human Body
- The human body consists of various systems that work together to maintain homeostasis and perform specific functions.
Anatomical Terms
- Anatomical descriptions are based on a person being in the anatomical position: standing erect, facing forward, with arms at the sides and legs together.
- Body planes:
- Sagittal plane: divides the body into equal right and left halves.
- Frontal (coronal) plane: divides the body into anterior and posterior portions.
- Transverse (axial) plane: divides the body into superior and inferior portions.
- Terms of relationship:
- Anterior (ventral): near the front.
- Posterior (dorsal): near the back.
- Superior (cranial): upward, or near the head.
- Inferior (caudal): downward, or near the feet.
- Medial: toward the midline.
- Lateral: farther from the midline.
- Proximal: near a reference point, closer to the trunk or point of origin.
- Distal: away from a reference point, further from the trunk or point of origin.
- Superficial: closer to the surface.
- Deep: further from the surface.
Movements
- Body movements occur at joints where two or more bones or cartilages articulate with each other.
- Types of movements:
- Flexion: decreases the angle between two bones.
- Extension: increases the angle between two bones.
- Abduction: movement away from the midline.
- Adduction: movement towards the midline.
- Rotation: movement around a longitudinal axis.
- Circumduction: movement in a circular direction.
Skin
- The skin is the largest organ in the body, accounting for 15-20% of total body mass.
- Functions of the skin:
- Protection: against abrasions, dehydration, and infection.
- Temperature regulation: through fat storage and sweat gland activation.
- Sensations: to touch, pain, and temperature.
- Endocrine regulation: secretion of hormones and synthesis of vitamin D.
- Exocrine secretions: secretion of sweat and sebum.
- Layers of the skin:
- Epidermis: outer protective layer.
- Dermis: dense connective tissue layer.
- Subcutaneous tissue: deepest layer.
- Appendages of the skin:
- Nails: horny covering on the tips of fingers and toes.
- Hair follicles: sheath of cells and connective tissue surrounding the root of a hair.
- Sebaceous glands: secrete lubricating oily matter into hair follicles.
- Sweat glands: secrete sweat and situated in the dermis.
Skeletal System
- The skeletal system supports, protects, and provides movement for the body.
- Divided into two regions:
- Axial skeleton: includes bones of the skull, vertebral column, ribs, and sternum.
- Appendicular skeleton: includes bones of the limbs, pectoral and pelvic girdles.
- Functions of the skeletal system:
- Support: provides a framework for the body.
- Protection: vital organs are protected by the skeleton.
- Movement: bones provide a system of levers and joints for movement.
- Storage of calcium and other salts/growth factors.
- Source of blood cells (bone marrow).
- Bones can be classified into 5 shapes:
- Long bones.
- Short bones.
- Flat bones.
- Irregular bones.
- Sesamoid bones.
- Long bones have the following regions:
- Epiphysis: ends of long bones.
- Epiphysial plate: site of growth in length.
- Metaphysis: site where the bone's shaft joins the epiphysis and epiphysial plate.
- Diaphysis: shaft of a long bone.
Joints
- Joints are the sites of union or articulation of two or more bones or cartilages.
- Types of joints:
- Fibrous joints: bones joined by fibrous connective tissue.
- Cartilaginous joints: bones joined by cartilage and fibrous tissue.
- Synovial joints: bones joined by a joint cavity filled with synovial fluid and surrounded by a capsule.
Muscular System
- The muscular system produces contractions that result in movement, maintenance of posture, changes in shape, or the propulsion of fluids through hollow tissues or organs.
- Three types of muscle:
- Skeletal muscle: striated muscle fibers attached to bone.
- Cardiac muscle: striated muscle fibers that make up the walls of the heart and proximal portion of the great veins.
- Smooth muscle: non-striated muscle fibers that line various organ systems and attach to hair follicles.
Ligaments and Tendons
- Ligaments: fibrous connective tissue that connects bones to bones and serve to hold structures together.
- Tendons: fibrous connective tissue that attaches muscles to bone or other body structures.
Cardiovascular System
- The cardiovascular system consists of the heart, vessels, and blood.
- Functions of the cardiovascular system:
- Transports oxygen and nutrients to cells.
- Transports waste products away from cells.
- Regulates body temperature.
- Maintains healthy blood pressure.
- Pulse points: locations where the pulse can be taken.
Lymphatic System
- The lymphatic system protects the body against infection, collects tissue fluids, and returns them to the circulatory system.
- Components of the lymphatic system:
- Lymph: a colorless, watery fluid that contains lymphocytes.
- Lymphocytes: cellular components of lymph, including T cells and B cells.
- Lymph vessels: an extensive network of vessels and capillaries in the peripheral tissues.
- Lymphoid organs: collections of lymphoid tissues, including lymph nodes, aggregates of lymphoid tissue, tonsils, thymus, spleen, and bone marrow.
Respiratory System
- The respiratory system provides oxygen to the body and eliminates carbon dioxide.
- Components of the respiratory system:
- Nose and paranasal sinuses.
- Pharynx and its subdivisions.
- Larynx and trachea.
- Bronchi, bronchioles, alveolar ducts/sacs, and alveoli.
- Lungs.
- Functions of the respiratory system:
- Filters and humidifies the air.
- Provides a large surface area for gas exchange.
- Helps regulate the pH of body fluids.
- Participates in vocalization.
- Assists the olfactory system.
Nervous System
- The nervous system integrates and regulates many body activities.
- Divided into two divisions:
- Central nervous system (CNS): includes the brain and spinal cord.
- Peripheral nervous system (PNS): includes the somatic, autonomic, and enteric nerves.
- Functions of the nervous system:
- Controls and coordinates body functions.
- Interprets and responds to sensory information.
- Regulates body temperature.
- Maintains homeostasis.### Nervous System
- The nervous system consists of the central nervous system (CNS) and peripheral nervous system (PNS)
- CNS: brain and spinal cord
- PNS: cranial nerves, spinal nerves
Neurons
- Neurons are called nerve cells
- Information comes to neurons through tree-like processes called dendrites or the neuronal body (soma)
- Neurons convey efferent (motor or output) information via action potentials that course along a single axon
- All neurons can be classified into three functional types:
- Sensory neurons: convey afferent impulses from peripheral receptors to the CNS
- Motor neurons: convey efferent impulses from the CNS to target cells (e.g., muscle cells)
- Interneurons: convey impulses between sensory and motor neurons in the CNS, forming integrated networks
Glial Cells
- Glial cells provide physical and metabolic support for CNS neurons
- Types of glial cells:
- Astrocytes: provide physical and metabolic support, release growth factors, and contribute to the formation of the blood-brain barrier
- Oligodendrocytes: responsible for the formation and maintenance of myelin in the CNS
- Microglia: phagocytic cells that participate in inflammatory reactions, remodel and remove synapses, and respond to injury
- Ependymal cells: line the ventricles of the brain and the central canal of the spinal cord, containing cerebrospinal fluid
- Schwann cells: surround all axons, provide trophic support, facilitate regrowth of PNS axons, and clean away cellular debris
Peripheral Nervous System
- Network of nerves that carry messages to and from the brain and spinal cord (CNS)
- Peripheral nerves include:
- 12 pairs of cranial nerves arising from the brain
- 31 pairs of spinal nerves arising from the spinal cord
Cranial Nerves
- 12 pairs of cranial nerves identified by name and Roman numerals I to XII
- Cranial nerves possess multiple functional components, including motor, sensory, and both
Spinal Nerves
- 31 pairs of spinal nerves form two major branches:
- Posterior (dorsal) ramus: small branch that courses dorsally to the back, conveying motor and sensory information to and from the skin and intrinsic back skeletal muscles
- Anterior (ventral) ramus: larger branch that courses laterally and ventrally, innervating all remaining skin and skeletal muscles of the neck, limbs, and trunk
Somatic Nervous System
- Sensory and motor fibers to skin, skeletal muscle, and joints
- One-neuron motor system: motor neuron in CNS, axon projects to peripheral target (e.g., skeletal muscle)
- Sensory (afferent) neuron resides in a peripheral ganglion (spinal ganglion) and conveys sensory information from skin, muscle, or joint to CNS (spinal cord)
- Dermatomes: areas of skin innervated by specific spinal root nerves (30 total, excluding the 1st cervical spinal nerve)
Autonomic Nervous System
- Sensory and motor fibers to smooth muscle (viscera, vasculature), cardiac muscle, and glands
- Two-neuron motor system: first neuron in CNS, second neuron in peripheral autonomic ganglion
- Preganglionic neuron: axon of the first neuron, postganglionic neuron: axon of the second neuron, then sends axon to target (smooth muscle, cardiac muscle, and glands)
Autonomic Nervous System Divisions
- Sympathetic nervous system: controls the body's "fight, flight, or fright" response
- Parasympathetic nervous system: helps control the body's response during times of rest ("rest and digest")
- These two systems balance each other out
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Description
Explore the basic structures and functions of human body systems, including skin, bone, muscle, joints, and more. Learn descriptive anatomical terms and understand the basics of human anatomy.
