Study Of Bodyfunction

Chapter 1

The Study of Body Function

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Human Physiology

Study of how the human body functions.

Pathophysiology: How physiological processes are

altered in disease or injury.


Scientific Method

Confidence in rational ability, honesty and humility.

Formulate hypothesis. Testing the hypothesis. Analyze results. Draw conclusion.


Homeostasis

Maintaining constancy of internal environment.

Dynamic consistency. Maintained by negative feedback

loops.


Feedback Loops

Sensor: Detects deviation from set point.

Integrating center: Determines the response.

Effector: Produces the response.




Negative Feedback

Defending the set point.

Reverse the deviation. Produces change in

opposite direction.


Hormone insulin restores plasma [glucose].www.freelivedoctor.com


Positive Feedback

Action of effectors amplifies the change.

Is in same direction as change. Examples:

Oxytocin (parturition) Voltage gated Na+ channels

(depolarization)


Primary Tissues

4 Different Primary Tissues: Muscle Nervous Epithelial Connective


Muscle Tissue

Specialized for contraction. 3 Types of Muscle Tissue:

Skeletal Cardiac Smooth


Skeletal Muscle

Voluntary muscle. Striated. Attach to bones at

both ends (tendons).

Arranged in parallel. Grade contraction.


Cardiac Muscle

Striated. Found only in

the heart. Interconnected. Intercalated

discs. Syncytium.


Smooth Muscle

Not striated. Gap junctions. Calmodulin. Peristalsis. Syncytium.


Nervous Tissue

Neurons (nerve cells): Specialized for conduction of action

potentials. Supporting cells:

Provide anatomical and functional support.


Neuron

Dendrites: Receive input.

Cell body: Nucleus. Metabolic center.

Axon: Conducts nerve

impulses.


Epithelial Tissue

Types of Epithelial Tissue: Cells that form membranes:

Squamous Columnar Cuboidal

Exocrine glands Endocrine glands


Squamous Cells

Flattened in shape.

Adapted for diffusion and filtration.

Line all blood vessels.


Cuboidal Cells

Cube-shaped cells.

Excretion, secretion and absorption.

Line kidney tubules, salivary ducts, and pancreatic ducts.


Columnar Cells

Taller column shaped cells.

Excretion, secretion and absorption.

May contain cilia. Line digestive tract

and respiratory passageways.


Exocrine Glands

Derived from cells of epithelial membranes.

Secretions are released through ducts. Simple tubes or modified as acini. Examples:

Tear glands Sweat glands Prostate glands


Endocrine Glands

Lack ducts. Secrete hormones into capillaries

within the body. May be discrete organs:

Primary functions are the production and secretion of hormones.


Connective Tissue

Large amounts of extracellular (ECF) material in the spaces between connective tissue cells.

4 Types of Connective Tissue: Connective tissue proper Cartilage Bone Blood


Connective Tissue Proper

Loose connective tissue: Scattered collagen and tissue fluid.

Dermis of skin Dense fibrous connective tissue:

Regular arranged. Collagen oriented in same direction.

Tendons Irregularly arranged.

Resists forces applied in many directions. Capsules and sheaths


Cartilage

Chondrocytes. Supportive and protective tissue. Elastic properties to tissues. Precursor to many bones. Articular surfaces on joints.


Bone

Hydroxyapatite crystals Osteoblasts:

Bone-forming cells Osteocytes:

Trapped osteoblasts: less active Osteoclasts:

Bone resorbing cells


Blood

Classified as connective tissue. Half its volume is plasma.


Organs

Organs: Composed of at least two primary

tissues. Serve different functions of the

organ.


Systems

Organs that are located in different regions of the body and perform related functions.

Examples: Skeletal system Cardiovascular system GI system


Body-Fluid Compartments

65-75% of total body weight H20. Intracellular compartment:

Fluid inside the cell. 2/3 of H20

Extracellular compartment: 1/3 H20 2 Subdivisions:

Blood plasma Interstitial fluid


Study Of Bodyfunction

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squamous cells

glands prostate glands

cells of epithelial

types of muscle tissue

cardiac muscle

smooth muscle

tear glands

endocrine glands lack