HUMAN PHYSIOLOGY PRINCIPLES OF 1libvolume7.xyz/nursing/bsc/1styear/physiology/...HUMAN PHYSIOLOGY THIRD EDITION Cindy L. Stanfield | William J. Germann PowerPoint ® Lecture Slides

PRINCIPLES OF

HUMAN PHYSIOLOGYTHIRD EDITION

Cindy L. Stanfield | William J. Germann

PowerPoint® Lecture Slides prepared by W.H. Preston, College of the Sequoias

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

1Introduction to

Physiology


Chapter Outline

I. What Is Physiology?

II. Organization of the Body

III. Challenging Homeostasis: Thermoregulation


Organization of the Body

• Levels of organization

• Cell

• Tissue

• Organ

• System


Organization of the Body

• Simplify by classifying

• Body has over 200 different cell types

• Cells can be put into four groups

• Neurons

• Muscle cells

• Epithelial cells

• Connective tissue cells


Major Tissue Types

• Based primarily on cell function

• Correspond to four major cell types

• Nerve tissue

• Muscle tissue

• Epithelium (epithelial tissue)

• Connective tissue


Neurons and Nerve Tissue

• Transmit signals for communication

• Have branches to receive or transmit

• Receive information from receptors

• Transmit information to muscles or glands

• Some neurons process information


Neurons and Nerve Tissue

Figure 1.2a


Muscle Cells

• Specialized to contract

• Can be voluntary or involuntary

• Examples of contraction

• Flexing of forearm

• Pumping of blood

• Mixing of food in the stomach


Muscle Cells

Figure 1.2b


Epithelial Cells and Epithelium

• Epithelium = sheet-like layer of cells

• Line external body surfaces

• Line hollow body tubes and organs

• Function as a barrier

• Function as a transport membrane


Epithelial Cells and Epithelium

Figure 1.2c


Epithelium: Glands

• Glands

• Formed from epithelium

• Manufacture a product

• Major classes of glands

• Exocrine glands

• Have ducts

• Endocrine glands

• No ducts, product into blood

• Product = hormone


Epithelium: Glands

Figure 1.3a


Epithelium: Glands

Figure 1.3b


Connective Tissue

• Most diverse of the four tissues

• Characterized by extracellular matrix

• Anchors and links structures of body


Connective Tissue

• Examples of connective tissue

• Bone

• Tendons

• Fat

• Blood


Connective Tissue

Figure 1.2d


Organ System

• Tissues contain similar cells

• Organs

• Composed of at least two tissue types

• Perform specific functions

• Organ System

• Collection of organs

• Perform particular task


Organ Systems

Table 1.1


A Simplified Body Plan

Figure 1.4


Body Fluids and Compartments

Figure 1.5a–c


Body Fluids and Compartments

Figure 1.5c–e


Body Fluid Compartments

• Internal environment = fluid surrounding cells =

extracellular fluid (ECF)

• 70 kg man

- Total body water = 42 liters

• 28 liters intracellular fluid (ICF)

• 14 liters extracellular fluid (ECF)

- Three liters plasma

- 11 liters interstitial fluid (ISF)


Homeostasis

• Ability to maintain a relatively constant internal

environment

• Conditions of the internal environment which are

regulated include

• Temperature

• Volume

• Composition


Homeostasis: Terms

• Negative feedback

• If a regulated variable decreases,

• System responds to make it increase, and vice versa

• Tends to be self correcting


Homeostasis: Terms

• Set point

• Expected value of regulated variable

• Examples

• Core body temperature = 37º C

• Blood glucose (sugar) = 100 mg/dL

• Blood pH = 7.4


Homeostasis: Terms

• Error signal

• Difference between value of set point and regulated

variable


Homeostasis: Terms

Figure 1.6c–d


Homeostasis: Components

• Structures enabling homeostasis

• Components include

• Receptors

• Integrating Centers

• Effectors

• Signals



• Receptors

• Sensors which detect stimuli

• Receptors include

• Thermoreceptors

• Chemoreceptors

• Baroreceptors



• Integrating center

• Orchestrates an appropriate response

• Often particular sets of neural circuits in brain



• Effectors

• Responsible for body responses

• Effectors include

• Muscles (smooth, striated, and cardiac)

• Glands



• Signals

• Allow components to communicate

• Input signal is from a receptor to an integrating

center

• Output signal is from an integrating center to an

effector

• Signals are chemical or via neurons


Negative Feedback Loop

Figure 1.7


Positive Feedback Loop

Positive feedback loops cause a rapid change in a

variable.

Figure 1.8


Homeostasis: Thermoregulation

• Core body temperature

• Humans: 37º C (98.6º F)

• Hypothermia = decrease in body temperature

• Hyperthermia = increase in body temperature

• Above 41º C is dangerous

• Above 43º C is deadly


Homeostasis: Thermoregulation

• Mechanisms of heat transfer between body and external

environment

• Radiation—thermal energy as electromagnetic waves

• Conduction—thermal energy through contact

• Evaporation—heat loss through evaporation of water

• Insensible water loss

• Sweating

• Convection—heat transfer by movement of fluid or air


Thermoregulation: Components

• Receptors = thermoreceptors

• Central: found in CNS (hypothalamus)

• Peripheral: found in PNS (mainly skin)

• Effectors

• Glands: sweat glands

• Muscles: skeletal muscles, and smooth muscle of

cutaneous blood vessels


Thermoregulation: Components

• Integrating center

• Thermoregulatory center in hypothalamus

• Signals

• Nerve impulses via neurons

• Chemicals via hormones


Thermoneutral Zone

• Range of outside temperature where

alterations in blood flow alone regulates

body temperature—25-30ºC

• Body temperature increase

• Blood flow to skin increases

• Body temperature decrease

• Blood flow to skin decreases


Thermoregulation

• Negative feedback control of body temperature

Figure 1.9a, b


Thermoregulation

Figure 1.9c


Fever

• Rise in core body temperature

• Accompanies infection

• White blood cells secrete pyrogens

• Body temperature set point increases

• Fever enhances immune response

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HUMAN PHYSIOLOGY PRINCIPLES OF 1libvolume7.xyz/nursing/bsc/1styear/physiology/...HUMAN PHYSIOLOGY THIRD EDITION Cindy L. Stanfield | William J. Germann PowerPoint ® Lecture Slides