Human Physiology The study of body function

1. Chapter 1
The Study of Body Function
Human Physiology

2. Human Physiology
• Study of how the human body
functions.
• Pathophysiology:
▫ How physiological processes are altered
in disease or injury.

3. Scientific Method
• Confidence in rational ability,
honesty and humility.
• Formulate hypothesis.
• Testing the hypothesis.
• Analyze results.
• Draw conclusion.

4. Homeostasis
• Maintaining constancy of internal
environment.
• Dynamic consistency.
• Maintained by negative feedback
loops.

5. Feedback Loops
• Sensor:
▫ Detects deviation from set point.
• Integrating center:
▫ Determines the response.
• Effector:
▫ Produces the response.

8. Negative Feedback
• Defending the set
point.
• Reverse the deviation.
• Produces change in
opposite direction.

9. Hormone insulin restores plasma [glucose].

11. Positive Feedback
• Action of effectors amplifies the
change.
• Is in same direction as change.
• Examples:
▫ Oxytocin (parturition)
▫ Voltage gated Na+
channels
(depolarization)

12. Primary Tissues
• 4 Different Primary Tissues:
▫ Muscle
▫ Nervous
▫ Epithelial
▫ Connective

13. Muscle Tissue
• Specialized for contraction.
• 3 Types of Muscle Tissue:
▫ Skeletal
▫ Cardiac
▫ Smooth

14. Skeletal Muscle
• Voluntary muscle.
• Striated.
• Attach to bones at
both ends
(tendons).
• Arranged in
parallel.
• Grade contraction.

15. Cardiac Muscle
• Striated.
• Found only in
the heart.
• Interconnected.
• Intercalated
discs.
• Syncytium.

16. Smooth Muscle
• Not striated.
• Gap junctions.
• Calmodulin.
• Peristalsis.
• Syncytium.

17. Nervous Tissue
• Neurons (nerve cells):
▫ Specialized for conduction of action
potentials.
• Supporting cells:
▫ Provide anatomical and functional
support.

18. Neuron
• Dendrites:
▫ Receive input.
• Cell body:
▫ Nucleus.
▫ Metabolic center.
• Axon:
▫ Conducts nerve
impulses.

19. Epithelial Tissue
• Types of Epithelial Tissue:
▫ Cells that form membranes:
 Squamous
 Columnar
 Cuboidal
▫ Exocrine glands
▫ Endocrine glands

20. Squamous Cells
• Flattened in
shape.
• Adapted for
diffusion and
filtration.
• Line all blood
vessels.

21. Cuboidal Cells
• Cube-shaped
cells.
• Excretion,
secretion and
absorption.
• Line kidney
tubules, salivary
ducts, and
pancreatic ducts.

22. Columnar Cells
• Taller column shaped
cells.
• Excretion, secretion
and absorption.
• May contain cilia.
• Line digestive tract
and respiratory
passageways.

23. 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

24. Endocrine Glands
• Lack ducts.
• Secrete hormones into capillaries
within the body.
• May be discrete organs:
▫ Primary functions are the production
and secretion of hormones.

25. 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

26. 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

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

28. Bone
• Hydroxyapatite crystals
• Osteoblasts:
▫ Bone-forming cells
• Osteocytes:
▫ Trapped osteoblasts: less active
• Osteoclasts:
▫ Bone resorbing cells

29. Blood
• Classified as connective tissue.
• Half its volume is plasma.

30. Organs
• Organs:
▫ Composed of at least two primary
tissues.
▫ Serve different functions of the organ.

31. Systems
• Organs that are located in different
regions of the body and perform
related functions.
• Examples:
▫ Skeletal system
▫ Cardiovascular system
▫ GI system

32. 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

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