Physiology of Cell, Tissues, Membranes and Glands.ppt

Physiology
of
Cell, Tissues,
Membranes
and
Glands

An Introduction to Cells
 Cell Theory
 Developed from Robert
Hooke’s research
 Cells are the Building
Blocks of all plants and
animals
 Cells are the smallest
Microscopic units that
perform all vital
physiological functions

Cell Types
 Prokaryotic
 Eukaryotic

Prokaryotic Cells Eukaryotic Cell
Bacterial cell Animal cell Plant cell

 Somatic cells (soma = body)
 Also known as Non-Reproductive cells.
 Performs all the body functions apart from reproduction
 Sex cells (germ cells)
 Reproductive cells
 Male sperm
 Female oocyte (a cell that develops into an egg)

Cell Functions
 Metabolism
– Use molecules for cellular functions, to make ATP and heat
 Molecule synthesis
– Different cells synthesize different molecules.
 Communication
– Cells produce and respond to chemical and electrical signals
 Reproduction and inheritance
– Most cells have a complete copy of all of our genetic information.
This is passed down from cell to cell and from parent to child

 A cell is surrounded by a watery medium known as the
extracellular fluid
 Extracellular fluid = interstitial fluid + plasma +
cerebrospinal fluid + synovial fluid
 The plasma membrane separates Intracellular fluid
(cytoplasm) from the Extracellular fluid (ECF)
 Intracellular fluid (Cytoplasm) = cytosol + organelles
 Cytosol = liquid
 Organelles are intracellular structures

Cytoplasm
 Intracellular fluid (Cytoplasm) = cytosol +
organelles
 Cytosol (watery matrix)
– Dissolved materials:
» nutrients, ions, proteins, and waste products
– Fluids
 Organelles = “little organs”
– Structures with specific functions

Organelles
 Nonmembranous organelles
 No membrane
 Direct contact with cytosol
 Includes the cytoskeleton, microvilli, centrioles, cilia,
ribosomes.
 Membranous organelles
 Covered with plasma membrane
 Isolated from cytosol
 Includes the nucleus, endoplasmic reticulum (ER), the
Golgi apparatus, lysosomes, peroxisomes, and
mitochondria

Nonmembranous Organelles
 The Cytoskeleton — structural proteins for
shape and strength
 Microfilaments
 Intermediate filaments
 Microtubules

 Microfilaments—thin filaments
composed of the protein actin
 Provide additional mechanical strength
 Pair with thick filaments of myosin for
muscle movement

 Intermediate filaments—mid-sized
between microfilaments and thick filaments
 Durable (collagen)
 Strengthen cell and maintain shape
 Stabilize organelles
 Stabilize cell position

 Microtubules—large, hollow tubes of
tubulin protein
 Strengthen cell and anchor organelles
 Change cell shape
 During cellular division they form the spindle
apparatus that attaches to chromosomes to
pull them to opposite ends of the dividing cell

Cellular Extensions
 Microvilli
 Cilia
 Flagella

Microvilli
 Microvilli
 Extension of the cell to
increase surface area of
the cell
 Found in brush border of
small intestine,
stereocilia of ear, WBC,
and oocyte.

Cilia
 Cilia
 Small, whip-like, motile
extensions of the cell
surface
 Ciliary movement move
fluids across the cell
surface
 Found in bronchioles
and fallopian tubes

Flagella
 Flagella
 Tail of sperm that consists of microtubules

Centrioles
 Pairs of microtubular structures
 Play a role in cell division

 Ribosomes
 Composed of two subunits containing = protein + RNA
 Made in nucleus and shipped to cytoplasm
 Build polypeptides in protein synthesis
 Two types
 Free ribosomes in cytoplasm:
– manufacture proteins for cell
 Fixed ribosomes attached to ER:
– manufacture proteins for cell membrane, lysosomes, or secretion

Membranous Organelles
 Membranous Organelles
1. Nucleus (double membrane)
2. Endoplasmic reticulum (ER)-
 Rough and Smooth ER
3. Golgi apparatus
4. Lysosomes
5. Mitochondria (double membrane)

Largest Organelle
Nucleus (stained yellow)

 Nucleus
 Houses the DNA
 Serves as the “Control Center of the Cell”
 Surrounded by two membranes, together called
the nuclear envelope
 The nuclear envelope is studded with nuclear pores.
 Nuclear pores regulate traffic into and out of the
nucleus.

 Inside the nucleus:
 Chromatin – composed of DNA + proteins
 Nucleolus – site of ribosome manufacture
 Nucleoplasm – fluid inside the nucleus

 Endoplasmic reticulum (ER)
 Continuous with outer nuclear envelope
 Has cisternae are storage chambers within
membranes
 Functions
 Synthesis of proteins, carbohydrates, cholesterol and lipids
 Storage of synthesized molecules and materials
 Transport of materials within the ER, to Golgi Apparatus, and
extracellularly
 Detoxification of drugs or toxins

 Smooth endoplasmic reticulum (SER)
 No ribosomes attached
 Synthesizes lipids and carbohydrates:
 Metabolizes lipids and breaks down glycogen  glucose
 Absorbs, synthesizes and transports lipids
 Detoxifies drugs, pesticides and carcinogens (liver/ kidney)
 Modified SER in skeletal muscle and cardiac muscle for
storage of Ca+2

 Rough endoplasmic reticulum (RER)
 Surface covered with ribosomes:
active in protein and glycoprotein synthesis
folds polypeptides protein structures
encloses products in vesicles that go to Golgi apparatus

Rough Endoplasmic Reticulum.

 Golgi Apparatus
 A stack of membranous sacs
 Vesicles pinch off from the ER to fuse with the
Golgi apparatus and empty their digestive
enzyme, protein or lipid contents.
 The lipids and proteins are then modified, sorted,
and sent to their appropriate destination in new
vesicles that bud off from the Golgi apparatus.
 Called as Packaging and Shipping Station of the
cell

Golgi Apparatus
Cisterns
New vesicles
forming
Transport
vesicle
from
trans face
Cis face—
“receiving” side of
Golgi apparatus
Transport vesicle
from rough ER
Trans face—
“shipping” side of
Golgi apparatus
Newly secreted
proteins
Secretory vesicle
New vesicles forming
Golgi
apparatus
Transport vesicle at
the trans face
Electron micrograph of the Golgi
apparatus (90,000)
Many vesicles in the process of pinching off
from the Golgi apparatus

Golgi Apparatus
 Receives substances from Endoplasmic
Reticulum, refines and packages them

Lysosomes
 Lysosomes = Called as “Suicide Bag” of the Cell.
powerful, acidic, enzyme containing vesicles.
Clean up inside cells
 Break down large molecules
 Digest ingested bacteria, viruses and toxins
 Recycle damaged organelles
 Eject wastes by exocytosis
Autolysis
 Auto = self, lysis = break
 Self-destruction of damaged cells:
–lysosome membranes break down
–digestive enzymes released
–cell decomposes
–cellular materials recycle

 Mitochondria
 Uses carbs, lipids, and proteins to
synthesize ATP
 Has outer and inner membranes separated
by the intermembrane space
 Inner membrane carries proteins involved in
ATP production
 Matrix is site of reactions that release energy
from nutrients

Plasma Membrane
 Functions of the Plasma Membrane
 Physical isolation
 Barrier
 Regulates exchange with environment
 Ions and nutrients enter
 Wastes eliminated and cellular products released
 Monitors the environment
 Extracellular fluid composition
 Chemical signals
 Structural support
 Anchors cells and tissues

Plasma Membrane
 Comprised of a phospholipid bilayer
 Hydrophilic heads — toward watery environment, both
sides
 Hydrophobic fatty-acid tails — inside membrane

Plasma Membrane
 Fluid Mosaic Model-describes the plasma
membrane as fluid, not static.

Plasma Membrane
 Membrane Proteins
 Integral proteins
 Span the membrane
 Peripheral proteins
 Bound to inner or outer surface of the membrane

Plasma Membrane
 Several Types of Membrane Proteins
 Anchoring proteins (stabilizers)
 Attach to inside or outside structures
 Recognition proteins (identifiers)
 Label cells as normal or abnormal
 Enzymes
 Catalyze reactions
 Receptor proteins
 Bind and respond to ligands (ions, hormones)
 Carrier proteins
 Transport specific solutes through membrane
 Channels
 Regulate water flow and solutes through membrane

Function of Connective
Tissue
• Function
• Supporting fabric
of all parts of the
body
• Bind other organs
together, hold
organs in place,
cushion them, and
fill space.

• Function
• Secretes a thin watery fluid called serous fluid that decreases
friction on organs during movement
• 3 Types
• Pleura — line thoracic cavity & lungs
• Serous pericardium — line the heart
• Peritoneum abdomen & abdominal organs ,largest serous
membrane
Serous Membranes aka Mesothelium

Physiology of Cell, Tissues, Membranes and Glands.ppt

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Physiology of Cell, Tissues, Membranes and Glands.ppt