MAINTAINING HOMEOSTASIS Organization Of The Human Body

Definition of Anatomy & Physiology Anatomy: study of Anatomy: study of  Structures  Relationship of structures

Definition of Anatomy & Physiology Physiology: study of the Physiology: study of the  Function of structures

First “Real” Anatomist William Harvey William Harvey   First to observe heart and circulation.  First to notice differences between warm and cold blooded animals. William Harvey

Levels of Structural Organization Chemical Chemical Cellular Cellular Tissue Tissue Organ Organ Organ system Organ system Organism Organism

Integration of Body Systems 8 organ systems 8 organ systems Integrated- they work together to keep the organism alive Integrated- they work together to keep the organism alive Strength of systems: they are specialized Strength of systems: they are specialized  therefore efficient Weakness of systems: interdependence Weakness of systems: interdependence  When one system fails, the others also begin to fail

Unifying Processes of Life Metabolism Metabolism  Catabolism = reactions that break down complex molecules into smaller ones (releases energy)  Anabolism=reactions that build complex molecules from smaller ones (requires energy) Responsiveness: detecting and reacting to stimuli Responsiveness: detecting and reacting to stimuli Movement: from organelles  cells  organism Movement: from organelles  cells  organism Growth: increase in body size Growth: increase in body size  # of cells, cell size, space around cells. Differentiation: process where unspecialized cells become specialized cells Differentiation: process where unspecialized cells become specialized cells Reproduction Reproduction  New cells for growth or repair  Organism: production of a new individual

Maintaining An Internal Balance Homeostasis (sameness/standing still) Homeostasis (sameness/standing still) Ensures that the internal environment remains constant, even if external conditions change Ensures that the internal environment remains constant, even if external conditions change Homeostasis is dynamic Homeostasis is dynamic Tortora Page: 7-9

Homeostasis and Blood Pressure Pressure-sensitive nerves in arteries sense higher BP. Pressure-sensitive nerves in arteries sense higher BP. Nerves send signal to brain. Nerves send signal to brain. Brain sends signals to slow heart rate. Brain sends signals to slow heart rate. Tortora Page: 9

Negative Feedback System: Blood Pressure

Homeostasis and Blood Pressure Blood pressure is the force behind blood as it flows through the arteries. Blood pressure is the force behind blood as it flows through the arteries. Systolic pressure: force exerted as ventricles contract: High BP reading Systolic pressure: force exerted as ventricles contract: High BP reading Diastolic pressure: force exerted as ventricles relax: Low BP Diastolic pressure: force exerted as ventricles relax: Low BP Increased heart rate and stroke volume increase BP. Increased heart rate and stroke volume increase BP.

Feedback Systems Feedback systems are either negative or positive. Feedback systems are either negative or positive.  Negative feedback systems reverse a change in a controlled condition  Positive feedback systems strengthen a change in a controlled condition. It is shut off by an event outside the system.  Most feedback systems in the human body are negative.  Childbirth is a positive feedback system Tortora Page: 9

Regulation of Glucose Levels The glucose roller coaster: The glucose roller coaster: –Low levels after sleep –High levels after breakfast, especially if lots of sugar is eaten –Low levels by lunch. –High levels after lunch high carb/ high sugar foods –Low levels by 2:00 Note the higher glucose levels after eating meals high in starches and sugars

Regulation of Glucose Levels If excess glucose is present in the blood:If excess glucose is present in the blood: Insulin is secreted by islets of Langerhans (beta cells) in pancreas. Insulin in the blood causes cells to take in glucose. –Glucose is also absorbed by liver cells which convert glucose to glycogen. (polysaccharide) –Net result: less glucose in the blood

Regulation of Glucose Levels When blood glucose levels are low:  Glucagon (hormone) is secreted by alpha cells in pancreas.  In the liver, glycogen is broken down into glucose and released into blood.  Net result: Glucose levels surrounding the cells stays fairly even throughout the day. See Figure 13.12, pg 360

Basic Anatomical Position 1. Individual is standing upright. 2. Arms placed at sides of the body. 3. Palms facing forward. 4. Feet flat on floor, toes forward. Tortora Page: 11-15

Directional Terms Used to locate various body Used to locate various body structures in relationship to each other. each other.  Superior/ Inferior (Cranial/ Caudal) (Cranial/ Caudal)  Anterior Vs Posterior (Ventral / Dorsal) (Ventral / Dorsal)  Medial/ Lateral  Intermediate  Proximal/ Distal  Superficial/ Deep Tortora 13

Planes & Sections Imaginary flat surfaces through the body. Imaginary flat surfaces through the body.  Sagittal plane  Midsagittal  Parasagital  Frontal (Coronal) plane  Transverse Tortora Page 15

Body Cavities Spaces within the body that contain organs. Spaces within the body that contain organs. Ventral body cavity Ventral body cavity  Thoracic (heart& lungs)  Pericaridal cavity  Pleural cavity  Abdominal (digestive, liver, reproductive)  Lining of cavity is called the peritoneum Tortora Page 16-17

Body Cavities The Dorsal cavity contains The Dorsal cavity contains 1. Cranial cavity 1. Cranial cavity  Cranial bones  the brain 2. Vertebral canal  Vertebral column (bones)  Spinal cord  Beginnings of spinal nerves Tortora Page 16