Slide 3

Muscle

• Muscle is an organ of the body made up of muscle tissue that can contract under the influence of nerve impulses.
• The muscle has a complex structure. It is formed by bundles muscle fibers, which in turn consist of the nucleus of the muscle fiber, contractile filaments, integumentary membrane and blood vessels. Outside, the muscle is covered with a connective tissue sheath - fascia.
• Muscles are attached to bones using tendons. Tendons are composed of dense, fibrous connective tissue and are highly durable.

Slide 4

Muscle work

• Muscles contracting. Or straining to produce work.
• Distinguish between dynamic and static work. Joint movement is provided by at least two muscles acting opposite to each other. Muscle work is controlled nervous system... This work is of a reflex nature.

Slide 5

Characteristics of the main groups of skeletal muscles

Slide 6

Muscle work

• Static muscle work is the active fixation of organs relative to each other and giving a certain position to the body, while the muscle develops tension without changing the length.
• The dynamic work of muscles is the displacement of some organs relative to others and the movement of the body in space, while the muscle changes its length and thickness.
• Muscle work is associated with energy expenditure. The energy for muscle contractions is provided by the ATP molecule.

Slide 7

Dynamic work of skeletal muscle

Slide 8

Prolonged muscle tension

• Long-term muscle tension leads to the development of fatigue. Fatigue is understood as a temporary decrease in muscle performance that occurs as they work.
• The causes of fatigue are associated with the accumulation of decay products of organic substances at the points of contact: neuron-neuron, neuron-muscle.

Slide 9

THEM. Sechenov found that with rhythmic work, fatigue occurs later, since in the intervals between contractions the muscle rests, intensive muscle work with a heavy load leads to rapid fatigue, the most optimal for muscles are medium loads and rhythm, and The best way restore muscle performance - active rest (with active activity of other muscles)

Biology lesson in grade 8

Theme: Muscles, their structure and function.

The purpose of the lesson : find out the features of the human muscular system associated with the upright position and work.

Lesson Objectives:

• Expand the principle of the location of muscles in relation to the joints; show that muscles together with bones form levers
• Give an elementary concept of physiology muscle contraction and fatigue
• Continue the formation of the ability to compare, analyze, highlight the main thing. To cultivate a respect for your health

Forms of organizing educational activities:

Combined lesson

Methods of teacher activity:heuristic conversation, execution of educational drawing on the board, organization of work with a microscope and visual aids.

Equipment:

Demo material: human skeleton, human torso, tables " skeletal muscle", Multimedia complex, electron microscope, micropreparations" muscle tissue ", presentation" structure and function of muscle tissue ", a fragment from the film from the series" people ".

Lesson plan:

1. Checking the material covered in the last two lessons
2. Learning new material

• Skeletal muscle structure
• Laboratory work
• The structure of the features of muscle tissue and its properties
• The main muscle groups, their localization and properties (s / r with a textbook)
• Nervous regulation of muscle activity

1. Anchoring

• Brainstorm

1. Homework

During the classes.

1. Checking the passed material

Biological dictation code (on screen)

1. Rib cage
2. Spine
3. Upper limb skeleton
4. Cerebral section of the skull
5. Upper limb belt
6. Lower limb skeleton
7. Facial section of the skull
8. Lower limb belt

1. The department is a pivot, support for the entire skeleton
2. The skeletal section, which includes the zygomatic and new bones
3. The part of the skeleton that performs protective functions in relation to the brain
4. Division of the skeleton, which includes the radius and humerus
5. Skeleton section, which includes the pelvic bones
6. The department is a support for the skeleton of the upper limbs
7. The skeletal section, which includes the femurs
8. Section of the skeleton, which includes the ribs and sternum

Answers: 1 – 2; 2-7; 3-4; 4-3; 5-8; 6-5; 7-6; 8-1.

Working on the board:

1. Draw the structure of the joint and reveal its functions
2. Indicate several joints on the skeleton performing different movements
3. Splint your comrade's forearm

The class evaluates the work of the comrades and, if necessary, makes adjustments.

The teacher asks the class the following questions:

• Why is it not recommended to ride foals on horseback?
• Why does a person have a broken fibula most often during a fall?
• Why is a splint applied to two sections located next to the damaged one?
• Why is a soft lining under the tire?
• Why are older bones more prone to fracture?
• What properties of bones provide their strength and relative lightness?
• During excavations in the mound, a skeleton was discovered. How to determine the sex of a person from the remains of the skeleton?

1. Learning new material

Moving on to the study of new material, the teacher draws attention to the fact that movement in the joints is produced by muscles.

A student's speech about the works of Leonardo da Vinci (material from the presentation).

Women and men have a different percentage of the tissues that make up their bodies.

Muscle tissue - women 35.8%; men 41.8%.

Bone tissue - 15.1%; 15.9%.

The lesson is based on independent work on the study of muscles using tables and self-observation of students. The work is, to some extent, research in nature, since students themselves find out some questions related to the work, development and location of human muscles.

Laboratory work.

Consider the structure:

1. Cross-striped
2. Cardiac
3. Smooth muscle tissue

Compare their structure

What conclusion can be drawn (display on the screen through an electron microscope)

1. The teacher describes the external structure of the muscle, indicates what properties are characteristic of muscle tissues, that the elongated shape of muscle fibers corresponds to the function of contractility, but what movement a muscle causes depends on its shape and the place of attachment to the bones of the skeleton.
2. Then the teacher explains the task, the order of work; perform the task together, but each student does the reporting task of his version individually.

• Read the text of the textbook on pages 118-121 and from the picture on page 120 find all the muscles indicated in the text
• Find your approximate location following muscles: chewing, deltoid, trapezoidal, biceps and triceps, gastrocnemius. Determine which movements they are participating in.
• Solve the following tasks:

• What is the state of the triceps muscle when the elbow is bent?
• What muscles in the arm are tense when we hold an object in an overhang in our outstretched arm?
• In what position are the flexors of the fingers relaxed?
• What are two examples of muscles that cause opposite movement in a joint during contraction?

Answers orally:

Option 1:

• What kind of leverage does biceps shoulder with forearm bones?
• Indicate muscles that are especially developed in a person due to the vertical position
• Indicate the muscles that act oppositely when bending the arm at the elbow

Option 2:

• What kind of lever is formed with the skull cervical muscles holding the head upright
• Indicate the muscles that exist only in humans and apes
• What muscles are involved in changing the volume of the chest?

After the end of the work, the students orally answer the questions of the assignment according to the options.

Teacher work.

The teacher calls the student (with well-developed muscles) to the blackboard. He is measured with a measuring tape, the circumference of the shoulder at the hand, lowered down. Then the student clenches the hand into a fist and bends the arm at the elbow. Sets the measurement in the volume of the shoulder. The student explains why this is happening and shows on the screen which muscles contracted during this movement and which relaxed.

The teacher asks questions:

• How is muscle movement regulated?
• Why do muscles contract?
• Why do the extensors relax when the flexors contract?

(students reasoning)

The teacher tells that this happens reflexively, and invites students to remember: what a reflex is, what nerves are, what neurons are.

Consider one of the simplest reflexes - knee. The teacher demonstrates the knee reflex on the evoked student and on the screen. Then, using the table on the board, they study the reflex arc of this reflex. Together they define the reflex and the structure of the reflex arc.

1. Nervous regulation of muscle activity. (teacher work)

Muscular movements in the body are of a reflex nature, because they are always a reaction to irritation of the receptors of the central nervous system. But these receptors can be very diverse. The muscle reflex can begin with irritation of the visual, auditory, and tactile receptors. Very often, muscle reflexes occur in response to stimulation of receptors located in the muscles and tendons themselves, as was the case in the knee reflex. When muscle contraction occurs, the receptors in it signal with the help of nervous excitement in the central nervous system that a movement reaction has occurred. This is very important for consistency of movement, but why, while the biceps muscle contracts, the muscle on the opposite side of the shoulder relaxes (a question to the class).

This coordination reveals a pattern associated with the ability of neurons not only to be excited and conduct excitation, but also to fall into a state of inhibition. When inhibition in neurons and nerves, the conduction of excitation stops. Naturally, if inhibition develops in the center of the neurons going to the muscle, then this muscle will relax. All this is due to nerve impulses coming from the central nervous system, which inform the brain about the state of the muscle. All voluntary movements of a person occur only with the participation of the cerebral cortex, and are impossible if the blood supply to certain areas of the cerebral cortex is disturbed (it shows on the screen the motor area where the centers of all voluntary movements are located).

1. Brainstorm.

• What muscles are used to express emotions
• What are the main properties of muscle tissue
• During excavations in the mound, a skeleton was found, can an experienced anatomist, based on the bones of the skeleton, decide whether he was an athlete, a loader, or a person leading a sedentary lifestyle
• It is noticed that a person falls in different ways: when he stumbles, he falls forward, and when he slips, he falls back. How can this phenomenon be explained?
• The teacher called the student to the blackboard, but before getting up, he bent forward over the desk, and only then straightened up and walked out to the blackboard. Can a person stand up without leaning forward? (if you don't answer any questions, this will be a problem to solve in the next lesson)

1. Homework assignment: pp. 116-122.

Preview:

To use the preview of presentations, create yourself a Google account (account) and log into it: https://accounts.google.com

Slide captions:

MUSCLES MUSCLE SYSTEM

MUSCLE SYSTEM, a collection of muscles and muscle bundles, usually united by connective tissue. Absent in unicellular organisms and sponges, well developed in vertebrates. The human muscular system includes about 400 skeletal muscles; in an adult, they make up 40% of the body weight. The muscular system is characterized by the following functions: motor, protective, form-building, energy.

Muscle is an organ of the body, consisting of muscle tissue that can contract under the influence of nerve impulses. The muscle has a complex structure. It is formed by bundles of muscle fibers, which in turn consist of the muscle fiber nucleus, contractile filaments, integumentary membrane and blood vessels. Outside, the muscle is covered with a connective tissue sheath - fascia. Muscles are attached to bones using tendons. Tendons are composed of dense, fibrous connective tissue and are highly durable.

Muscle work Muscles by contracting. Or straining to produce work. Distinguish between dynamic and static work. Joint movement is provided by at least two muscles acting opposite to each other. The nervous system controls the muscles. This work is of a reflex nature.

Characteristics of the main groups of skeletal muscles group Main muscles of function Head muscles: 1. Chewing 2. Mimic Chewing, temporal, external, internal, pterygoid Circular muscles of the mouth and eyes, buccal cranials Set in motion lower jaw Open and close the mouth, eyes, change facial expression, speech articulation Neck muscles (superficial and deep) Subcutaneous sternoclavicular, scalene Support and set in motion the head, neck, lower jaw, raise the first and second ribs Back muscles Trapezoidal, broadest, diamond-shaped and others. They set in motion the shoulder blades, head, neck, arms, ribs during breathing, maintain the vertical position of the body. Muscles of the chest Large and small pectorals, anterior dentate, external and internal intercostal muscles Set in motion shoulder girdle, ribs during breathing Abdominal muscles Oblique, transverse and straight ( abdominal Press), diaphragm Set the torso in motion (tilted forward and to the sides); respiratory movements Muscles of the limbs a) upper; b) lower; Biceps, triceps, deltoid, subscapularis, muscles of the forearm and hand Greater sciatica, biceps femoris, gastrocnemius, triceps lower legs, muscles of the foot Move the arms Move the legs

Static muscle work is the active fixation of organs relative to each other and giving a certain position to the body, while the muscle develops tension without changing the length. The dynamic work of muscles is the displacement of some organs relative to others and the movement of the body in space, while the muscle changes its length and thickness. Muscle work is associated with energy expenditure. The energy for muscle contractions is provided by the ATP molecule (

Dynamic work of skeletal muscle excitation Central nervous system Flexion center Extension center excitation inhibition inhibition inhibition excitation Muscles (biceps) Muscles (triceps) contraction relaxation contraction relaxation arousal

Prolonged muscle tension leads to the development of fatigue. Fatigue is understood as a temporary decrease in muscle performance that occurs as they work. The causes of fatigue are associated with the accumulation of decay products of organic substances at the points of contact: neuron-neuron, neuron-muscle.

Them. Sechenov found that with rhythmic work, fatigue occurs later, since in the intervals between contractions the muscle rests, intensive muscle work with a heavy load leads to rapid fatigue, the most optimal for muscles are medium loads and rhythm, and the best way to restore muscle performance is active rest (with vigorous activity of other muscles)

Muscles of the arm and hand

Muscles of the hand

Calf muscles

Muscles of the trunk

MUSCLE SYSTEM MUSCLE SYSTEM, a collection of muscles and muscle bundles, usually united by connective tissue. Absent in unicellular organisms and sponges, well developed in vertebrates

Abdominal muscles

Test Your Knowledge How Do Muscles Do Work? What kind of work is called dynamic? Static? What work is done while holding the load? How do flexor and extensor muscles work? Is it true that all muscle activity is of a reflex nature? Justify your answer. Why do muscles get tired? What determines the rate of development of muscle fatigue?

Basic concepts

Abdomen muscle,

Tendon,

Muscle head,

Tail muscle,

Muscle antagonists

Synergistic muscles

Muscle bundle

Muscle fiber

Training effect,

Motor unit,

Dynamic work,

Static work,

Types and properties of muscle tissue

• Excitability
• Contractility
• Conductivity
• Elasticity

The microscopic structure of the muscles. Muscle bundle

Under what letter are smooth and striated muscles indicated? A-; B-.

What is indicated by numbers

Macroscopic structure of muscles

Muscle head,

Tail muscle,

Muscle antagonists

Synergistic muscles

Aponeurosis?

Muscles of the human body

Muscles of the head

Muscles of the head

Human muscular system:

1 - tendon helmet and cranial muscles;

2 - temporal muscles; 3 - circular muscle eyes;

4 - muscle lifting the corner of the mouth;

5 - buccal muscle;

6 - muscle lowering the lower lip;

7 - subcutaneous muscle neck;

8 - chin muscle;

9 - muscle lowering the corner of the mouth;

10 - circular muscle of the mouth;

11 - chewing muscle;

12 - large zygomatic muscle;

13 - nasal muscle;

14 - muscle of the auricle .

Muscles of the human body

Muscles of the neck

Muscles of the human body

Trunk muscles in front

Muscles of the human body

Back muscles of the trunk

Muscles of the human body

Arm muscles

Muscles of the human body

Leg muscles

Motor unit

a group of muscle fibers innervated by one motor neuron that contract simultaneously

The work of motor units during muscle contraction

Motor unit (DE)

The contraction is weak if a small number of DEs are included in the work;

Strong contraction - alternate contraction of several% CU

The energy of muscle contraction. Training effect

The results are very fast at the beginning of the workout, then the results grow more slowly, because it is not the number of muscle fibers that increases, but the number of contractile filaments (actin and myosin) and mitochondria

Independent work

P. 70 "Regulation of the work of antagonist muscles"

Make a neural arc of regulation of muscle movements involved in

A) retention of cargo

B) moving cargo

Regulation of muscle work. Dynamic and static work

Nervous arc regulation of muscle movements involved in

A) holding the load - the brain - the excitatory signal of the biceps muscle (while the triceps is relaxed)

B) moving cargo -

brain - the excitatory signal of the biceps muscle (while the triceps is relaxed), then to the triceps (the biceps relaxes)