1. SRM VALLIAMMAI ENGINEERING COLLEGE
(An Autonomous Institution)
DEPARTMENT OF MEDICAL ELECTRONICS
1910302 – ANATOMY AND HUMAN PHYSIOLOGY
III Semester
Regulation 2019
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3. TOPICS TO BE COVERED
STRUCTURE OF CELL
STRUCTURE AND FUNCTIONS OF SUB ORGANELLES
CELL MEMBRANE & TRANSPORT ACROSS CELL MEMBRANE
ACTION POTENTIAL & CELL TO CELL SIGNALING
CELL DIVISION
TYPES OF SPECIALISED TISSUES
TISSUES - FUNCTIONS
5. CELL:
cells are the structural units of all living
things.
The human body contains 50 to 100
trillion of these tiny building blocks
6.
7. CELL THEORY:
Four concepts collectively known as the cell theory:
A cell is the basic structural and functional unit of living organisms. So, when you
define cell properties, you are in fact defining the properties of life.
The activity of an organism depends on the collective activities of its cells.
According to the principle of complementarity, the activities of cells are dictated
by their structure (anatomy), which determines function (physiology).
Continuity of life has a cellular basis.
8. In general, all cells have three main regions or parts—
nucleus
plasma membrane
cytoplasm
The nucleus is usually located near the center of the cell. It is surrounded by the
semifluid cytoplasm, which in turn is enclosed by the plasma membrane, which
forms the outer cell boundary
10. NUCLEUS:
Nucleus The control center
The genetic material, or deoxyribonucleic acid (DNA), is a blueprint that contains
all the instructions needed for building the whole body
More specifically, DNA has genes, which carry the instructions for building
proteins.
DNA is also absolutely necessary for cell reproduction. A cell that has lost or
ejected its nucleus (for whatever reason) is destined to “self-destruct.”
SHAPE: Nucleus is most often oval or spherical, its shape usually conforms to the
shape of the cell
11. The nucleus has three recognizable regions or structures:
nuclear envelope
nucleolus
chromatin
12. Nuclear envelope:
The nuclear boundary is a double membrane barrier called the nuclear envelope,
or nuclear membrane
Between the two membranes is a fluid-filled space
At various points, the two layers of the nuclear envelope fuse, generating
openings called nuclear pores.
Like other cellular membranes, the nuclear envelope allows some but not all
substances to pass through it, but substances pass through it much more freely
than elsewhere because of its relatively large pores.
The nuclear membrane encloses a jellylike fluid called nucleoplasm in which other
nuclear elements are suspended
13. Nucleolus:
The nucleus contains one or more small, darkstaining, essentially round bodies
called nucleoli
Nucleoli are sites where cell structures called ribosomes are assembled.
Most ribosomes eventually migrate into the cytoplasm, where they serve as the
actual sites of protein synthesis
14. Chromatin:
When a cell is not dividing, its DNA is carefully wound around proteins called
histones to form a loose network of “beads on a string” called chromatin that is
scattered throughout the nucleus.
When a cell is dividing to form two daughter cells, the chromatin threads coil and
condense to form dense, rodlike bodies called chromosomes (chromo = colored,
soma = body)— much the way a stretched spring becomes shorter and thicker
when allowed to relax.
15. PLASMA MEMBRANE:
The flexible plasma membrane is a fragile, transparent barrier that contains the
cell contents and separates them from the surrounding environment
Although the plasma membrane is important in defining the limits of the cell, it is
much more than a passive envelope, or “baggie.”
unique structure allows it to play a dynamic role in many cellular activities
16. Fluid mosaic model:
The structure of the plasma membrane consists of two phospholipid (fat) layers
arranged “tail to tail,” with cholesterol and floating proteins scattered among them
Some phospholipids may also have sugar groups attached, forming glycolipids.
The proteins, some of which are free to move and bob in the lipid layer, form a
constantly changing pattern or mosaic, hence the name of the model that
describes the plasma membrane
17. CYTOPLASM:
Cellular region between the nuclear and plasma membranes.
Consists of
fluid cytosol containing dissolved solutes
organelles (the metabolic machinery of the cytoplasm)
inclusions (stored nutrients, secretory products, pigment granules).
18. The cytosol is semitransparent fluid that suspends the other elements. Dissolved in
the cytosol, which is largely water, are nutrients and a variety of other solutes
Inclusions are chemical substances that may or may not be present, depending on
the specific cell type. They include the lipid droplets common in fat cells, glycogen
granules abundant in liver and muscle cells, pigments such as melanin in skin and
hair cells, mucus and other secretory products, and various kinds of crystals.
The organelles are specialized cellular compartments that are the metabolic
machinery of the cell. Each type of organelle is specialized to carry out a specific
function for the cell as a whole
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20.
21. CELL TYPES:
Cells that connect body parts
Fibroblast
Erythrocyte
Cells that cover and line body organs
Epithelial cell
Cells that move organs and body parts
Skeletal muscle cell
Cardiac muscle cell
Smooth muscle cell
Cell that stores nutrients
Fat cell
Cells that fights disease
White Blood cell
Cells that gather information and
controls body function
Nerve cell
Cells of Reproduction
23. The fluid environment on both sides of the plasma membrane is an example of a
solution
SOLVENT ?
SOLUTE ?
Intracellular fluid (collectively, the nucleoplasm and the cytosol) is a solution
containing small amounts of gases (oxygen and carbon dioxide), nutrients, and salts,
dissolved in water. So too is extracellular fluid, or interstitial fluid, the fluid that
continuously bathes the exterior of our cells.
The plasma membrane is a selectively permeable barrier.
Selective permeability means that a barrier allows some substances to pass through
while excluding others.
24. Transport of substances through the cell membrane:
Passive processes include diffusion and filtration
Active processes (active transport and vesicular transport) use energy (ATP) provided by
the cell.
25. Diffusion:
Diffusion is the movement of a substance from an area of its higher concentration
to an area of its lower concentration. It occurs because of kinetic energy of the
molecules themselves; no ATP is required. The diffusion of dissolved solutes
through the plasma membrane is simple diffusion. The diffusion of water across
the plasma membrane is osmosis. Diffusion that requires a protein channel or
carrier is facilitated diffusion
26. Filtration:
Filtration is the movement of substances through a membrane from an area of
high hydrostatic pressure to an area of lower fluid pressure. In the body, the
driving force of filtration is blood pressure.
27. Active transport:
In active transport, substances are moved across the membrane against an
electrical or a concentration gradient by proteins called solute pumps.
This accounts for the transport of amino acids, some sugars, and most ions.
28. The two types of ATP-activated vesicular transport are exocytosis and endocytosis.
Exocytosis moves secretions and other substances out of cells; a membrane-
bounded vesicle fuses with the plasma membrane, ruptures, and ejects its
contents to the cell exterior.
Endocytosis, in which particles are taken up by enclosure in a plasma membrane
sac, includes phagocytosis (uptake of solid particles), pinocytosis (uptake of fluids),
and the highly selective receptor-mediated endocytosis. In the latter, membrane
receptors bind with and internalize only selected target molecules.
34. The cell life cycle is the series of changes a cell goes through from the time it is
formed until it divides.
The cell division has two major phases:
mitosis (nuclear division)
cytokinesis (division of the cytoplasm)
35. The function of cell division is to produce more cells for growth and repair
processes.
Because it is essential that all body cells have the same genetic material, an
important event always precedes cell division:
The DNA molecule (the genetic material) is duplicated exactly in a process called
DNA replication
Nucleotides join in a complementary way: Adenine (A) always bonds to thymine
(T), and guanine (G) always bonds to cytosine (C). Hence, the order of the
nucleotides on the template strand also determines the order on the new strand.
36. Mitosis:
Mitosis is the process of dividing a nucleus into two daughter nuclei with exactly
the same genes as the “mother” nucleus.
As explained previously, DNA replication precedes mitosis, so that for a short time
the cell nucleus contains a double dose of genes
The stages of mitosis include the following events:
Prophase
Metaphase
Anaphase
Telophase
37.
38. Cytokinesis:
Cytokinesis, or the division of the cytoplasm, usually begins during late anaphase
and completes during telophase.
A contractile ring made of microfilaments forms a cleavage furrow over the
midline of the spindle, and it eventually squeezes, or pinches, the original
cytoplasmic mass into two parts.
Thus, at the end of cell division, two daughter cells exist. Each is smaller with less
cytoplasm than the mother cell had but is genetically identical to the mother cell.
The daughter cells grow and carry out normal cell activities until it is their turn to
divide.
39. Protein synthesis:
Protein synthesis involves both DNA (the genes) and RNA.
a. A gene is a segment of DNA that carries the instructions for building one protein. The
information is in the sequence of bases in the nucleotide strands. Each three-base
sequence (triplet) specifies one amino acid in the protein.
b. Messenger RNA carries the instructions for protein synthesis from the DNA (gene) to
the ribosomes. Transfer RNA transports amino acids to the ribosomes. Ribosomal RNA
forms part of the ribosomal structure and helps coordinate the protein building process.
42. Groups of cells that are similar in structure and function are called tissues and
represent the next level of structural organization
The four primary tissue types interweave to form the fabric of the body :
Epithelial tissues covering
Connective tissues support
Nervous tissues control
Muscle tissues movement
43. Epithelial tissues:
Epithelium generally has the unique characteristics:
Except for glandular epithelium, epithelial cells fit closely together to firm continuous sheet.
Neighboring cells bound together at many points by specialized cell junctions, including
desmosomes and tight junctions.
The membranes always have one free (unattached) surface or edge apical surface
The anchored (basal) surface of epithelium rests on a basement membrane, a structureless
material secreted by both the epithelial cells and the connective tissue cells deep to the
epithelium
Epithelial tissues have no blood supply of their own (that is, they are avascular) and depend
on diffusion from the capillaries in the underlying connective tissue for food and oxygen.
If well nourished, epithelial cells regenerate themselves easily.
44. Types of epithelial cells:
Epithelia are named according to
number of layers (simple, stratified)
cell shape (squamous, cuboidal,
columnar)
45. CONNECTIVE TISSUE:
The distinguishing characteristics of connective tissue include the following:
Variations in blood supply: Most connective tissues are well vascularized, but there are
exceptions. Tendons and ligaments, for example, have a poor blood supply, and
cartilages are avascular. Consequently, all these structures heal very slowly when injured.
Extracellular matrix: Connective tissues are made up of many different types of cells plus
varying amounts of a nonliving substance found outside the cells, called the
extracellular matrix.
46. Types of connective tissues:
The major connective tissue classes are:
Bone
Cartilage
Dense connective tissue
Loose connective tissue
Blood
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50. MUSCLE TISSUES:
Muscle tissues are highly specialized to contract, or shorten, which generates the
force required to produce movement.
There are three types of muscle tissue:
Skeletal
Cardiac
Smooth
52. NERVOUS TISSUE:
All neurons receive and conduct electrochemical impulses from one part of the
body to another
The structure of neurons is unique Their cytoplasm is drawn out into long
processes (extensions), as long as 3 feet or more in the leg, which allows a single
neuron to conduct an impulse to distant body locations.
A special group of supporting cells called neuroglia insulate, support, and protect
the delicate neurons in the structures of the nervous system—the brain, spinal
cord, and nerves.
54. Functions of epithelial tissues:
Epithelial functions include
Protection
Absorption
Filtration
Secretion
For example:
Epithelium of the skin protects against bacterial and chemical damage, and the epithelium lining the respiratory tract
has cilia, which sweep dust and other debris away from the lungs.
Epithelium specialized to absorb substances lines some digestive system organs such as the stomach and small
intestine, which absorb food nutrients into the body.
In the kidneys, epithelium both absorbs and filters. Glandular epithelium forms various glands in the body.
Secretion is a specialty of the glands, which produce such substances as sweat, oil, digestive enzymes, and mucus
55.
56. Functions of connective tissues:
Connective tissues perform many functions, but they are primarily involved in
Protecting
Supporting
Binding together other body tissues.
57. Functions of muscle tissue:
Muscle tissue: Contracts to cause movement, contractile structure
Muscles attached to bones (skeletal)
Muscles of heart wall (cardiac)
Muscles of walls of hollow organs (smooth)
58. Functions of nervous tissue:
Two major functional characteristics:
Irritability
Conductivity
