The document discusses the muscular system of insects. It describes the three main types of muscle tissue - striated, cardiac, and smooth muscle. It notes that insects only have striated muscle. The structure and organization of insect muscle fibers and myofibrils are explained. Insect muscles are classified as either synchronous or asynchronous skeletal muscles. The mechanisms of muscle attachment to the exoskeleton via tonofibrillae and apodemes are outlined. Finally, the key functions of the muscular system in insects are listed.
Structure of integument its function, moulting.pptxvineetha43
Slide 1
Insect body wall is called as Integument or Exoskeleton.
It is the external covering of the body which is ectodermal in origin
It is rigid, flexible, lighter and stronger
Slide 2
Structure of body wall consists of an outer non cellular part (cuticle), an inner cellular layer (epidermis), basement membrane
Epidermis - It is an inner unicellular layer resting on basement membrane
It’s functions:
i. Cuticle secretion &
Secretion of moulting fluids
ii. Digestion and absorption of old cuticle
iii. Wound repairing
iv. Gives surface look, protection, muscle attachment
v. Water-tight barrier against desiccation, and a sensory interface with environment.
Slide 3
Cuticle - It is an outer non cellular layer comprising three sub layers Sub layers of cuticle
i. Endocuticle
Innermost and thickest layer made up of chitin and arthropodin. This layer is colourless, soft and flexible
ii. Exocuticle
Outer layer, much thicker & harden with composition of chitin and sclerotin. This layer is dark in colour and rigid
Structure of integument its function, moulting.pptxvineetha43
Slide 1
Insect body wall is called as Integument or Exoskeleton.
It is the external covering of the body which is ectodermal in origin
It is rigid, flexible, lighter and stronger
Slide 2
Structure of body wall consists of an outer non cellular part (cuticle), an inner cellular layer (epidermis), basement membrane
Epidermis - It is an inner unicellular layer resting on basement membrane
It’s functions:
i. Cuticle secretion &
Secretion of moulting fluids
ii. Digestion and absorption of old cuticle
iii. Wound repairing
iv. Gives surface look, protection, muscle attachment
v. Water-tight barrier against desiccation, and a sensory interface with environment.
Slide 3
Cuticle - It is an outer non cellular layer comprising three sub layers Sub layers of cuticle
i. Endocuticle
Innermost and thickest layer made up of chitin and arthropodin. This layer is colourless, soft and flexible
ii. Exocuticle
Outer layer, much thicker & harden with composition of chitin and sclerotin. This layer is dark in colour and rigid
Embryology is the branch of biology which deals with the growth and development of an embryo of
an organism, commencing with the union of male and female gametes.
Embryology includes the development of the fertilized egg and embryo and the growth of the organ
system.
Development of an insect from egg to adult can be divided into two parts
a.Early embryonic development - takes place inside the egg and
b. Post embryonic development – occurring outside the egg.
Embryology is the branch of biology which deals with the growth and development of an embryo of
an organism, commencing with the union of male and female gametes.
Embryology includes the development of the fertilized egg and embryo and the growth of the organ
system.
Development of an insect from egg to adult can be divided into two parts
a.Early embryonic development - takes place inside the egg and
b. Post embryonic development – occurring outside the egg.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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The muscular system is responsible for the movement of the human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person's body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
1. Kingdom of Saudi Arabia
Al Imam Mohammad Ibn Saud Islamic University
College of Science
Department of Biology
Entomology
353 Bio
T. Amani Alsharidah
1441 – 2019
3. Introduction
Muscles power all the movements, external and internal, in insects.
Insect muscles show high levels of homology to these vertebrate
muscles in their structure, protein content, contractility and regulation.
Insect muscles are mostly translucent, colourless or grey, though the flight
muscles often show a yellowish or brown tinge.
In most skeletel muscles, especially those of the appendages, one end of the
muscle is attached to a movable part.
Cuticular invaginations or apodemes, in the form of cords, bands or plate like
structures, may provide the true sites of attachment.
4. The cells that constitute this tissue are referred to as muscle fibers .
Classification of muscle tissue:
Three types of muscles are usually distinguished according to striations into
striated (skeletal and cardiac)and unstriated (smooth).
1. The most familiar is the skeletal ,voluntary .This type is named skeletal muscle
because it is connected to the skeleton and is concerned with body
movements.
2. The second type forms the contractile portion of the heart and is therefore
called cardiac muscle .It is striated but involuntary in action. They contract
spontaneously.
3. The third type is also involuntary and because it does not exhibit striations, it
is known as smooth muscle. It is found as part of the walls of the viscera.
The muscular Tissue
6. The muscular Tissue
Each type of muscle has its own particular characteristics, but all types of
muscles exhibit common features which are:
Muscle cells are elongated in shape.
1. The plasma membrane of the muscle fiber is called sarcolemma and its
cytoplasm is called sarcoplasm.
2. Organoids and inclusions are present in the cytoplasm (mitochondria and
smooth ER which is called sarcoplasmic reticulum).Glycogen is the main
muscle inclusions.
3. Muscle fibers are mesodermal in origin.
7. Insect muscle
Vertebrates and many non-insect invertebrates have striated and smooth muscles, but
insects have only striated muscles.
The entire muscle is enclosed by a sheath of dense CT called epimysium .
Thin fibrous septa ,that constitute the perimysium exetnd the epimysium and divide the
muscle into bundles of muscles fibers called fascicles .
The epimysium sends delicate CT sheets to surround individual muscle fibers in each
fascicle. These connective tissue sheets constitute the endomysium.
Blood vessels and nerves penetrate the epimysium to the perimysium and endomysium
but Lymphatic vessels are only present in the epimysium and perimysium.
8. Insect muscle
Skeletal muscle fibers :
Long cylindrical cells, enclosed by the sarcolemma.
The fibers are multinucleated ,pale oval nuclei that lie under its sarcolemma.
The sarcoplasm is filled with numerous myofibrils.
The myofibrils, Two principal types of myofilaments have been identified ;thick
and thin ones .
1. The thick filament is composed of a protein called myosin.
2. The thin myofilaments are attached to the Z line and are composed of a protein
called actin together with two other associated protein called tropomyosin and
troponin.
Muscle contraction involves the sliding of filaments past each other, stimulated
by nerve impulses.
10. Classification of skeletal muscle in insect
There are several different muscle types but in general it classified to:
1. Synchronous Skeletal Muscles :-
Vast majority of insect muscles are synchronous muscles. Each contraction is driven
by a single neural stimulus. The form and arrangement of the myofibrils in
synchronus muscles is very variable.
2. Asynchronous Skeletal Muscles :-
In these neural stimulation is asynchronous with respect to contraction. The
specialized asynchronous muscles typically have large cylindrical myofibrils, that’s
why they are sometimes called fibrillar.
11. Muscle attachments
Vertebrates’ muscles work against an internal skeleton, but the muscles of insects
must attach to the inner surface of an external skeleton.
As musculature is mesodermal and the exoskeleton is of ectodermal origin, fusion
must take place.
This occurs by the growth of tonofibrillae, fine connecting fibrils that link the
epidermal end of the muscle to the epidermal layer.
At the site of tonofibrillar attachment, the inner cuticle often is strengthened
through ridges or apodemes, which, when elongated into arms, are termed
apophyses.
These muscle-attachment sites, often include resilin to give an elasticity that
resembles that of vertebrate tendons.
12.
13. Function of muscular system
1. Support of the body.
2. Helps maintain posture.
3. Movement of the limbs, including ovipositor.
4. Movement of the wings-insects.
5. Movement of the viscera.
6. Locomotion.
7. Closure of spiracles.
8. Operation of various pumps such as cibarial pump and the pumping of the
poison glands.
9. Generation of heat by ‘shivering’.
