Skeletal muscle presentation. Presentation on the topic "structure and function of muscles". chewing muscle

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Biology lesson in grade 8

Subject: Muscles, their structure and functions.

The purpose of the lesson : to find out the features of the human muscular system associated with the vertical position and labor.

Lesson objectives:

• To reveal 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 the physiology of muscle contraction and fatigue
• Continue the formation of the ability to compare, analyze, highlight the main thing. Cultivate respect for your health

Forms of organization of educational activities:

Combined lesson

Teacher activities:heuristic conversation, execution of an educational drawing on the board, organization of work with a microscope and visual aids.

Equipment:

Demonstration material: human skeleton, human torso, tables "skeletal muscles", multimedia complex, electron microscope, micropreparations "muscle tissue", presentation "structure and functions of muscle tissue", a fragment from the film from the series "human".

Lesson plan:

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

• The structure of the skeletal muscle
• 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 material covered

Biological dictation code (on screen)

1. Rib cage
2. Spine
3. Upper limb skeleton
4. Cerebral region of the skull
5. Upper limb belt
6. Skeleton of the lower extremities
7. Facial region of the skull
8. Belt of the lower extremities

1. The department is the core, the support for the entire skeleton
2. Department of the skeleton, which includes the zygomatic and new bones
3. Part of the skeleton that performs protective functions in relation to the brain
4. The part of the skeleton that includes the radius and humerus
5. The part of the skeleton that includes the pelvic bones
6. The department is a support for the skeleton of the upper limbs
7. The part of the skeleton that includes the femur
8. The part of the skeleton that includes the ribs and sternum

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

Board work:

1. Draw the structure of the joint and reveal its functions
2. Indicate on the skeleton several joints that perform various movements
3. Put a splint on 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 is the fibula most often broken in a person during a fall?
• Why put a splint on two departments located next to the damaged one?
• Why do they put a soft lining under the tire?
• Why are the bones of older people more prone to fracture?
• What properties of bones provide their strength and relative lightness?
• During excavations in the barrow, a skeleton was discovered. How to determine the sex of a person from the remains of the skeleton?

1. Learning new material

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

Speech by a student on the works of Leonardo da Vinci (material from the presentation).

Women and men do not have the same percentage of 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 introspection of students. The work is, to some extent, research in nature, because. students themselves find out some issues related to the work, development and location of human muscles.

Laboratory work.

Consider building:

1. striated
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 the muscle tissue is characterized by, that the elongated shape of the muscle fibers corresponds to the function of contractility, but what movement the 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, according to the drawing on page 120, find all the muscles indicated in the text
• Find the approximate location of the following muscles: chewing, deltoid, trapezius, biceps and triceps, gastrocnemius. Determine what movements they are involved in.
• Solve the following tasks:

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

Answers verbally:

1 option:

• What kind of leverage does the biceps brachii muscle form with the bones of the forearm?
• Specify the muscles that are especially developed in humans in connection with the vertical position.
• Specify the muscles that act oppositely when bending the arm in the elbow joint

Option 2:

• What kind of leverage do the neck muscles form with the skull, holding the head upright?
• Specify the muscles that exist only in humans and great apes
• What muscles are involved in changing the volume of the chest?

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

The work of the teacher.

The teacher calls the student (with well-developed muscles) to the blackboard. They measure the circumference of the shoulder with a centimeter tape at the arm lowered down. Then the student squeezes the hand into a fist and bends the arm at the elbow. Sets the measurement in the volume of the arm. 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 extensor muscles relax when flexors contract?

(student reasoning)

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

Consider one of the simplest reflexes - the knee. The teacher demonstrates the knee jerk on the called student and on the screen. Then, according to the table on the board, they study the reflex arc of this reflex. Together they give the definition of the reflex and the structure of the reflex arc.

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

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

This coordination manifests a regularity associated with the ability of neurons not only to be excited and conduct excitation, but also to fall into a state of inhibition. When braking 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 connected with 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 (shows on the screen the motor area where the centers of all voluntary movements are located).

1. Brainstorm.

• What muscles express emotions
• What are the main properties of muscle tissue
• During excavations in the barrow, a skeleton was found, can an experienced anatomist 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 differently: when he stumbles, he falls forward, and when he slips, he falls back. How to explain this phenomenon?
• The teacher called the student to the blackboard, but before standing up, he leaned forward over the desk, and only then straightened up and went to the blackboard. Can a person stand up without leaning forward? (if they do not answer some questions, this will be a problem for solving it in the next lesson)

1. Homework: pp. 116-122.

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Slides captions:

MUSCLES MUSCULAR SYSTEM

MUSCLE SYSTEM, a set of muscles and muscle bundles, usually united by connective tissue. Absent in unicellular and sponges, well developed in vertebrates. The human muscular system consists of about 400 skeletal muscles, in an adult they make up 40% of body weight. The following functions are characteristic of the muscular system: motor, protective, shaping, energy.

Muscles are 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 core of the muscle fiber, contractile filaments, the integumentary membrane and blood vessels. Outside, the muscle is covered with a connective tissue sheath - fascia. Muscles are attached to bones by tendons. Tendons are made up of dense fibrous connective tissue and are highly durable.

Muscle work Muscles contracting. Or straining to do the work. Distinguish between dynamic and static work. Movement in the joints is provided by at least two muscles that act opposite to each other. Muscles are controlled by the nervous system. This work is reflexive in nature.

Characteristics of the main groups of skeletal muscles group Main muscles of function Muscles of the head: 1. Chewing 2. mimic , speech articulation Neck muscles (superficial and deep) Subcutaneous sternocleidomastoid, scalene Support and move the head, neck, lower the lower jaw, raise the first and second ribs Back muscles Trapezius, latissimus, rhomboid, etc. They move the shoulder blades, head, neck, arms, ribs during breathing, maintain the vertical position of the body. Chest muscles Pectoralis major and minor, serratus anterior, external and internal intercostals Move the shoulder girdle, ribs during breathing Abdominal muscles Oblique, transverse and rectus (abdominal press), diaphragm Move the torso (tilted forward and to the sides); respiratory movements Limb muscles a) upper; b) lower; Biceps, triceps, deltoid, subscapularis, forearm and hand muscles Big ischium, biceps femoris, gastrocnemius, triceps calf, foot muscles Move arms Move legs

Static work of muscles is an active fixation of organs relative to each other and giving a certain position to the body, while the muscle develops tension without changing its 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 the expenditure of energy. The energy for muscle contraction is provided by the ATP molecule (

Dynamic work of the skeletal muscle excitation Central nervous system Center of flexion Center of extension excitation inhibition inhibition excitation Muscles (biceps) Muscles (triceps) contraction relaxation contraction relaxation excitation

Prolonged muscle tension leads to the development of fatigue. Fatigue is understood as a temporary decrease in the performance of muscles 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 during 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 the muscles are medium loads and rhythm, and the best way to restore muscle performance is active rest. (with active activity of other muscles)

Muscles of the arm and hand

Muscles of the hand

Leg muscles

Trunk muscles

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

Abdominal muscles

Test your knowledge How do muscles do work? What is dynamic work? Static? What work is done while holding the load? How do flexor and extensor muscles work? Is it true that all muscular activity is reflex in nature? Justify your answer. Why do muscles get tired? What determines the rate of development of muscle fatigue?

Basic concepts

abdominal muscles,

Tendon,

muscle head,

tail muscle,

Antagonist muscles,

Synergistic muscles,

muscle bundle,

muscle fiber,

training effect,

motor unit,

dynamic work,

static work,

Types and properties of muscle tissue

• Excitability
• Contractility
• Conductivity
• Elasticity

Microscopic structure of muscles. muscle bundle

Which letter represents smooth and striated muscles? A-; B-.

What is indicated by the numbers

Macroscopic structure of muscles

muscle head,

tail muscle,

Antagonist muscles,

Synergistic muscles,

Aponeurosis?

Muscles of the human body

Muscles of the head

Muscles of the head

The human muscular system:

1 - tendon helmet and supracranial muscles;

2 - temporal muscles; 3 - circular muscle of the eye;

4 - muscle that raises the corner of the mouth;

5 - buccal muscle;

6 - muscle lowering the lower lip;

7 - subcutaneous muscle of the neck;

8 - chin muscle;

9 - muscle that lowers the corner of the mouth;

10 - circular muscle of the mouth;

11 - chewing muscle;

12 - a large zygomatic muscle;

13 - nasal muscle;

14 - auricle muscle .

Muscles of the human body

Neck muscles

Muscles of the human body

Muscles of the trunk in front

Muscles of the human body

Muscles of the back of the body

Muscles of the human body

arm muscles

Muscles of the human body

leg muscles

motor unit

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

The work of motor units during muscle contraction

Motor unit (MU)

The reduction is weak if a small amount of DU is included in the work;

Strong contraction - successive contraction of several % MU

Energy of muscle contraction. Training effect

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

Independent work

Page 70 "Regulation of the work of antagonist muscles"

Draw up the neural arch that regulates the movements of the muscles involved in

A) hold the load

B) moving cargo

Muscle regulation. Dynamic and static work

The neural arch regulates the movements of the muscles involved in

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

B) moving cargo -

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

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Muscular system

• Muscular system, a set of muscles and muscle bundles, usually united by connective tissue. Absent in unicellular and sponges, well developed in vertebrates.
• The human muscular system consists of about 400 skeletal muscles, in an adult they make up 40% of body weight.
• The following functions are characteristic of the muscular system: motor, protective, shaping, energy.