1 - Lecture An Introduction to Anatomy and Physiology

An Introduction to Studying the Human Body Learning Outcomes 1-1 Explain the importance of studying anatomy and physiology. 1-3 Define anatomy and physiology, describe the origins of anatomical and physiological terms, and explain the significance of Terminologia Anatomica (International Anatomical Terminology). 1-4 Explain the relationship between anatomy and physiology, and describe various specialties of each discipline.

An Introduction to Studying the Human Body Learning Outcomes 1-6 Explain the concept of homeostasis. 1-7 Describe how negative feedback and positive feedback are involved in homeostatic regulation, and explain the significance of homeostasis.

An Introduction to Studying the Human Body Classification of Living Things Humans and many other animals are vertebrates Characterized by a segmented vertebral column Common characteristics suggest the same path in evolution Homeostasis The goal of physiological regulation and the key to survival in a changing environment

1-1 Anatomy and Physiology Directly Affect Your Life Is the oldest medical science 1600 B.C. Physiology Is the study of function Biochemistry Biology Chemistry Genetics

1-3 Anatomy and Physiology Anatomy – meaning to cut apart or dissect Describes the structures of the body What they are made of Where they are located Associated structures Physiology Is the study of: Functions of anatomical structures Individual and cooperative functions

1-4 Relationships between Anatomy and Physiology Gross anatomy, or macroscopic anatomy, examines large, visible structures Surface anatomy: exterior features Regional anatomy: body areas Systemic anatomy: organ systems Developmental anatomy: from conception to death Clinical anatomy: medical specialties

1-4 Relationships between Anatomy and Physiology Microscopic anatomy examines cells and molecules Cytology: study of cells and their structures cyt- = cell Histology: study of tissues and their structures

1-4 Relationships between Anatomy and Physiology Cell physiology: processes within and between cells Organ physiology: functions of specific organs Systemic physiology: functions of an organ system Pathological physiology: effects of diseases

1-6 Homeostasis Homeostasis All body systems working together to maintain a stable internal environment Systems respond to external and internal changes to function within a normal range (body temperature, fluid balance)

1-6 Homeostasis Mechanisms of Regulation Autoregulation (intrinsic) Automatic response in a cell, tissue, or organ to some environmental change Extrinsic regulation Responses controlled by nervous and endocrine systems

1-6 Homeostasis Receptor Control center Effector Receives the stimulus Processes the signal and sends instructions Effector Carries out instructions

Figure 1-2 The Control of Room Temperature RECEPTOR Information affects Normal condition disturbed Thermometer STIMULUS: Room temperature rises HOMEOSTASIS CONTROL CENTER (Thermostat) Air conditioner turns on Air conditioner turns off Normal room temperature RESPONSE: Room temperature drops 20° 30° 40° Room temperature (°C) Normal range 22 Normal condition restored EFFECTOR Sends commands to Air conditioner turns on Time In response to input from a receptor (a thermometer), a thermostat (the control center) triggers an effector response (either an air condi- tioner or a heater) that restores normal temperature. In this case, when room temperature rises above the set point, the thermostat turns on the air conditioner, and the temperature returns to normal. With this regulatory system, room temperature fluctuates around the set point. 13

1-7 Negative and Positive Feedback The Role of Negative Feedback The response of the effector negates the stimulus Body is brought back into homeostasis Normal range is achieved

Figure 1-3 Negative Feedback in the Control of Body Temperature RECEPTORS Temperature sensors in skin and hypothalamus Information affects Normal temperature disturbed CONTROL CENTER STIMULUS: Body temperature rises HOMEOSTASIS Thermoregulatory center in brain Normal body temperature Vessels dilate, sweating increases Vessels constrict, sweating decreases RESPONSE: Increased heat loss, body temperature drops 37.2 Normal temperature restored EFFECTORS Sends commands to Body temperature (°C) Normal range 37 • Sweat glands in skin increase secretion • Blood vessels in skin dilate 36.7 Time Events in the regulation of body temperature, which are comparable to those shown in Figure 12. A control center in the brain (the hypothalamus) functions as a thermostat with a set point of 37°C. If body temperature exceeds 37.2°C, heat loss is increased through enhanced blood flow to the skin and increased sweating. The thermoregulatory center keeps body temperature fluctuating within an acceptable range, usually between 36.7 and 37.2°C. 15

1-7 Negative and Positive Feedback The Role of Positive Feedback The response of the effector increases change of the stimulus Body is moved away from homeostasis Normal range is lost Used to speed up processes

Figure 1-4 Positive Feedback: Blood Clotting Clotting accelerates Positive feedback loop Chemicals Chemicals Blood clot Damage to cells in the blood vessel wall releases chemicals that begin the process of blood clotting. The chemicals start chain reactions in which cells, cell fragments, and soluble proteins in the blood begin to form a clot. As clotting continues, each step releases chemicals that further accelerate the process. This escalating process is a positive feedback loop that ends with the formation of a blood clot, which patches the vessel wall and stops the bleeding. 17

1-7 Negative and Positive Feedback Systems Integration Systems work together to maintain homeostasis Homeostasis is a state of equilibrium Opposing forces are in balance Dynamic equilibrium — continual adaptation Physiological systems work to restore balance Failure results in disease or death

Table 1-1 The Roles of Organ Systems in Homeostatic Regulation 19

The study of the general form and superficial markings of an organism is called ________ anatomy.

Gross Surface Systemic Regional surgical

B) Surface

Which of the following is arranged in correct order from the most COMPLEX to the SIMPLEST?

A) cellular, tissue, molecular, system, organ, organism B) molecular, cellular, tissue, organ, system, organism C) tissue, cellular, molecular, organ, system, organism D) organ, organism, molecular, cellular, tissue, system E) organism, system, organ, tissue, cellular, molecular

E) organism, system, organ, tissue, cellular, molecular

The kidneys and ureters are organs of the ________ system.

A) endocrine B) digestive C) respiratory D) urinary E) lymphatic

D) urinary

The maintenance of a constant internal environment in an organism is termed ?

positive feedback. homeostasis. C) negative feedback. D) effector control. E) integration.

B) homeostasis.

An anatomical term that means the same as ventral:

posterior inferior C) abdominal D) anterior E) superior

D) anterior

An example of a receptor in a negative feedback loop controlling body temperature would be ?

A) temperature sensors on the skin that detect a stimulus. B) sweat glands that increase secretion. C) regulatory centers that send commands to an effector. D) effectors that cause blood vessels to dilate. E) sweat glands that act like effectors.

A) temperature sensors on the skin that detect a stimulus.