The study of body function

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 H
2
0.
•Intracellular compartment:
▫Fluid inside the cell.
▫2/3 of H
2
0
•Extracellular compartment:
▫1/3 H
2
0
▫2 Subdivisions:
Blood plasma
Interstitial fluid

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