Cell & cell organelles physiology for nurses

Cell and cell organelles for nurses

1. Physiology
•What is Physiology ?
•Why is it important to learn ?
•Books to refer :
•Guyton and Hall Textbook of Medical Physiology (Int : 14
th
Edition, SA 3
rd
Edition)
•Textbook of Physiology –A.K.Jain(10
th
Edition)
•B D Chaurasia’sApplied Anatomy and Physiology –for BSc Nursing Students
•Tortora’s Principles of Anatomy and Physiology
•Anatomy and Physiology for Nurses : InderbirSingh
•Human Physiology : NM Muthayya

2. C
CELL & CELL
ORGANELLES
Dr. Sheffy Sabu Thomas
Junior Resident, Dept. of Physiology

3. Learning Objectives
•What is cell?
•Organisation of cell
•Cell structure
•Cell organelles

4. The cell
•Building blocks of the body
•Structure for the body’s tissues and organs
•Ingest nutrients and convert them to energy
•Perform specialized functions
•Hereditary code: controls the synthesis of
substances and replication
Organ
system
Organs
Tissues
Cells

5. Organisation
of cell
•Protoplasm: different
substances that make up the
cell
•Protoplasm is composed
mainly of five basic
substances—
•Water
•Electrolytes
•Proteins
•Lipids
•Carbohydrates
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

6. Organization of the cell
•Water: 70% to 85%.
•Substances are dissolved / suspended
•Ions: potassium, magnesium, phosphate, sulphate, bicarbonate
•Provide inorganic chemicals for cellular reactions
•Proteins: 10% to 20% of the cell mass
•Structural proteins: Microtubules, actin, myosin
•Functional proteins: tubular-globular; enzymes
•Lipids: 2%, fat soluble substances, phospholipids and cholesterol, triglycerides
•Form cell membrane and other membranous structures
•Carbohydrates: glycoprotein molecules, nutrition, glycogen, dissolved glucose

7. Cell organelles
•Cell membrane
•Cytoplasm
•Endoplasmic reticulum
•Golgi Apparatus
•Lysosomes
•Peroxisomes
•Secretory Vesicles
•Mitochondria
•Cell Cytoskeleton
•Nucleus
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

8. Cell
membrane
•Envelops the cell
•Thin, pliable, elastic structure
•Thickness: 7.5 to 10 nanometres
•Composition: 55% proteins, 25%
phospholipids, 13% cholesterol, 4%
other lipids, and 3% carbohydrates.
•Lipid barrier impedes penetration by
water-soluble substances
•Lipid bilayer: phospholipids,
sphingolipids, and cholesterol
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

9. Cytoplasm and its organelles
•Filled with minute and large dispersed particles and organelles.
•Cytosol: The jelly-like fluid portion of the cytoplasm in which the particles are
dispersed
•Contains mainly dissolved proteins, electrolytes, and glucose.
•Dispersed in the cytoplasm are neutral fat globules, glycogen granules, ribosomes,
secretory vesicles,
•Five especially important organelles—the endoplasmic reticulum, the Golgi
apparatus, mitochondria, lysosomes, and peroxisomes.

10. Endoplasmic
reticulum
•Network of tubular structures
calledcisternae and flat
vesicular structures
•Endoplasmic matrix –filled
with watery substance
•Lipid bilayer, similar to cell
membrane
•Multiple enzyme systems
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

11. ER -Functions
•Function: Cell metabolic functions.
•Helps process molecules made by the cell and transports them to
their specific destinations inside or outside the cell
•Rough (Granular) ER: Ribosomes
•function to synthesize new protein molecules in the cell
•Smooth (Agranular) ER: no ribosomes
•Synthesis of lipid substances

12. Golgi apparatus
•Closely related to the ER
•Membrane similar to smooth ER
•Four or more stacked layers of
thin, flat, enclosed vesicles lying
near one side of the nucleus
•Prominent in secretory cells
•Processes substances synthesized
by ER to form lysosomes,
secretory vesicles, and other
cytoplasmic components
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition
Ref: GK Pal comprehensive textbook of Medical Physiology, 2
nd
edition

13. Lysosomes
•Formed by breaking off from the Golgi apparatus and dispersed throughout
the cytoplasm
•Intracellular digestive system
(1) damaged cellular structures;
(2) food particles that have been ingested by the cell; and
(3) unwanted matter such as bacteria
•Hydrolase (digestive) enzymes: Breaks organic compound by combining one
end with H
+
and other with OH
-
•Membrane: prevents action hydrolases outside lysosomes
•Lysosomal storage diseases: accumulation of materials in the lysosome

14. Peroxisomes
•Formed by budding from or by division of smooth endoplasmic reticulum
•Oxidases :
•β-oxidation of long chain fatty acids
•Combine oxygen with hydrogen ions (different intracellular chemicals) to form hydrogen
peroxide (H2O2)
•Catalase: liberate oxygen from H2O2, Protect from oxidative stress
•Peroxins: protein chaperons
•Zellweger syndrome, infantile Refsumdisease, Brown-Schilder’sdisease
(Adenoleukodystrophy)

15. Secretory granules
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

16. Mitochondria
•Powerhouses of the cell
•Number of mitochondria relates to
activity of cell
•Two lipid bilayer protein membranes:
•Outer membrane
•Inner membrane: infoldings, cristae
•Cristae: oxidative enzymes
•Forms ATP
•Self-replicative, has DNA
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

17. Nucleus
•Control centerof the cell
•Sends messages to the cell to
grow and mature, replicate, or
die
•Large quantities of DNA, genes
•Nuclear Membrane: outer
membrane is continuous with the
endoplasmic reticulum
•Nuclear pores
•Nucleoli: highly staining structure,
accumulation of large amounts of
RNA and proteins
Ref: GK Pal comprehensive textbook of Medical Physiology, 2
nd
edition

18. CC
CYTOSKELETON

19. C
CYTOSKELETON
•Network of fibrillar
proteins
•Microfilaments
•Intermediate
filaments
•Microtubules: tubulins
•Actin, myosin, dynein
•Gives structural
support and help in
intracellular transport
and cellular mobility
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

20. Microfilaments
•Contribute to the maintenance of and change in cell shape and regulation of
cell functions
•Long solid filaments, 7nm
•Actin: Globular –G actin (subunits), Filamentous : F actin
•Polar: Polymerisation at one end and depolymerize at other end
•Functions:
•Major contractile fibersof the cell: change in cell shape and cell movement
•Contractile phenomena within the cytoplasm: Phagocytosis, secretion, transport
•Movement for : cell division, microvilli
•Integrin receptors to form focal adhesion complexes (FAC)–where cell is
attached to surface

21. Intermediate Filaments
•8 to 14 nm diameter
•Integrate the organelles within the cytoplasm
•Skeletal network for the cell and resist rupture of cell
from external pressure
•Cell markers: cell specific, Diagnostics
•Cytokeratin: epithelial cells,
•Vimentin: fibroblast

22. Microtubules
•Long hollow tubular structures, 25 nm
•Subunits of globular proteins called
tubulins (α-tubulin and β-tubulin)
Centrioles -γtubulins.
•Dynamic structure: Disaggregating
(disassembly) and re-aggregating
(assembly)
•Cytotoxic drugs: Inhibit the assembly
•Temperature sensitive
•Extends into cilia and flagella
•Kinesin and dynein are microtubule-
basedmolecular motors

23. Functions
•Microtubules serve as cytosolic guide rails for transport of
substances
•Maintenance of cell strength and cell shape.
•Formation of spindles that move chromosomes during mitotic cell
division.
•Pillars for structure and function of cilia.
•Cell motility.

24. Cytoskeleton

25. Molecular motors
•Help in the movement of
various cell parts, proteins and
organelles within the cell
cytoplasm.
•100kDa ATPases
•Two domains:
•Attaches to cargo
•Moves along microtubule
Kinesin
•Cargo toward the
negative terminal or
positive terminal of
microtubules
Dynein
•Cytoplasmic form:
moves cargo toward
the negative terminals
of microtubules
•Axonemal form: in cilia
and flagella

26. Microtubules with molecular motors

27. CCINTERCELLULAR
JUNCTIONS

28. Intercellular connections

29. Tight junction/ zonula occludens
•Epithelium (GIT, urinary tract)
•Toward the apical region
•cell membrane of neighbouring cells fuse with each other that obliterates the
intercellular space
•Proteins: occludin, claudins and junctional adhesion molecules (JAMs)
•Function: selective permeability barrier: prevent transport of macromolecules
•Presence of leaky channels: permits small size watersoluble particles
(paracellular transport)
•Blood-brain barrier

30. Anchoring Junctions
Cell to Cell
•Desmosomes
•Focal thickening of two adjacent
cell membranes (25nm)
•Desmogleinsand cadherins
•Zonula Adherens
•Located below the base of tight
junctions
•Attachment for intracellular
microfilaments
•Cadherins
Cell to Basal Lamina
•Hemidesmosomes
•Similar to desmosomes
•Integrins
•Focal Adhesions
•Connect cell to the basal lamina
•associated with actin filaments

31. Gap junction
•Cell come together (3nm)
•Transmembrane proteins known as
connexons
•Connexon: six identical protein subunits
called connexins
•Surrounds an aqueous channel
•Allows substances to pass through
•Functions: Electrical synapse, passage of
solutes

33. CCFUNCTIONS

34. •Endocytosis:Ingestion by cell
Large particles enter the cell
by a specialized function of
the cell membrane called
endocytosis
•Pinocytosis: Fluid, most large
macromolecules, such as
proteins enter cells
•Phagocytosis:large particles
(rather than molecules) enters
the cell
•Exocytosis
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

35. C
SYNTHESIS

36. C
ENERGY
PRODUCTIO
N AND
UTILIZATION
Ref: Guyton and Hall, textbook of medical Physiology, 14
th
international edition

37. C
SUMMARY

38. CTHANK YOU