Introduction to the Human Body Chapter one

Understanding the Human Body Curiosity Illnesses, injuries, death Obtained knowledge regarding the human body as science and medicine advanced

Anatomy: examines the structures, or morphology, or body parts – their forms, organization -tomy: (Greek) cutting up Anatomists rely on examination Physiology: considers the functions of body parts – what they do and how they do it Also Greek origin; relationship to nature Physiologists rely on experimentation

A few definitions… Regional anatomy: study of anatomy based on regions or divisions of the body; emphasis on relations between the structures of that region Systemic anatomy: study of anatomy based on body systems and their functioning throughout the body Gross anatomy: study of anatomy that is visible to the naked eye; macroscopic Microscopic anatomy: study of anatomy at the microscopic level; cells

Levels of Organization The human body is composed of parts within parts, which vary in complexity

Maintenance of Life Requirements of Organisms Water  metabolic processes; transport of substances Food/Nutrients  energy Oxygen  release energy from food substances Heat  regulation of metabolic reaction rates Pressure  breathing (atmospheric); blood circulation (hydrostatic) Although we require the aforementioned, these factors alone are not enough to ensure survival; quality and quantity matter.

Homeostasis Equilibrium of the body’s internal environment produced by the interaction of organ systems and regulatory processes (feedback systems). Homeostasis is a dynamic condition in response to changing conditions. So important that it requires most of our metabolic energy

Continued… Body maintains homeostasis through a number of self-regulating control systems – homoeostatic mechanisms Receptors: provide information about the stimuli in the internal environment Control center: includes a set point, tells what a particular value should be (body temperature) Effectors: elicit responses that alter conditions in the internal environment ; muscles or glands

Feedback Mechanisms Negative feedback: almost all homeostatic control mechanisms are negative feedback mechanisms. These mechanisms reduce the variable back to its original state or “ideal value”. Blood sugar  receptors sense the change  pancreas (control center) secretes insulin  blood sugar levels reduce Positive feedback:  the output enhances the original stimulus. Child birth: oxytocin is released that intensifies and speeds up contractions. Blood clotting: vessel is damaged, platelets start to cling to the injured site and release chemicals that attract more platelets. The platelets continue to pile up and release chemicals until a clot is formed. Just remember that positive feedback mechanisms enhance the original stimulus and negative feedback mechanisms inhibit it.

Body Cavities and Terminology Day two – chapter one

Anatomical Position Standing straight, body erect Feet slightly apart Palms facing forward Thumbs point away from body Mrs. Schwab is my favorite science teacher ever

Body Planes Sagittal: divides the body into right and left parts Frontal/coronal: divides the body into anterior and posterior parts Transverse: divides the body into superior and inferior parts Deep breaths Schwab Deep Breaths

Superior Inferior

Any fluid filled space in a multicellular organism Body Cavities Dorsal cavity: protects the nervous system, and is divided into two subdivisions Cranial cavity: within the skull; encases the brain Vertebral cavity: runs within the vertebral column; encases the spinal cord Ventral cavity: houses the internal organs (viscera), and is divided into two subdivisions Thoracic Abdominopelvic Any fluid filled space in a multicellular organism From Jacob Abbott

Thoracic cavity (contains heart Cranial cavity (contains brain) Dorsal body cavity Thoracic cavity (contains heart and lungs) Ventral body cavity (thoracic and abdominopelvic cavities) Vertebral cavity (contains spinal cord) Diaphragm Abdominal cavity (contains digestive viscera) Pelvic cavity (contains bladder, reproductive organs, and rectum) Key: Dorsal body cavity Ventral body cavity (a) Lateral view

Thoracic Cavity Thoracic cavity is subdivided into two pleural cavities, the mediastinum, and the pericardial cavity Right & Left Pleural cavities: each houses a lung Mediastinum: contains the pericardial cavity; surrounds the remaining thoracic organs Pericardial cavity: encloses the heart

(b) Anterior view Cranial Vertebral Superior mediastinum Thoracic Pleural cavity Cranial Vertebral Pericardial Thoracic (contains heart and lungs) Key: Dorsal body cavity Ventral body cavity (b) Anterior view Figure 1.9b

Abdominopelvic cavity The abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm Composed of two subdivisions Abdominal cavity– contains the stomach, intestines, spleen, liver, gall bladder Pelvic cavity– lies within the pelvis and contains the bladder, reproductive organs, and rectum

Body Cavities Diaphragm Abdominal cavity (contains digestive viscera) Abdomino- pelvic cavity Key: Dorsal body cavity Pelvic cavity (contains bladder, reproductive organs, and rectum) Ventral body cavity Figure 1.9b

Facial/Head Cavities Oral and digestive – mouth and cavities of the digestive organs Nasal –located within and posterior to the nose Orbital – house the eyes Middle ear – contains bones (ossicles) that transmit sound vibrations Synovial – joint cavities

Abdominopelvic Regions

Abdominopelvic Quadrants Right upper Left upper Right lower Left lower Figure 1.12