HW Packet #7 Muscles and Skin

​Muscles and Skin

By Victor Castillo

MUSCLES

• Works with skeletal system to allow body to move

• Works with skeletal system to give body shape

• Produces heat

Functions of muscular system:

Poll

What is a function of the muscular system?

• Helps you think

• Breaks down food

• Circulates oxygen around our body

• allows for movement

Lines the internal organs such as the intestines and stomach

Also involuntary muscle

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Smooth Muscle

Composes the walls of the heart.

Involuntary muscle and therefore not subject to conscious control​

Cardiac Muscle

three types of muscle tissue

Skeletal Muscle

​Attaches to the skeleton via tendons to produce bodily movement.

Skeletal muscle is voluntary, meaning one can consciously control it.​

Multiple Choice

Which type of muscle tissue lines the internal organs such as the intestines and stomach?

• Cardiac Muscle

• Smooth Muscle

• Skeletal Muscle

Multiple Choice

Cardiac Muscle

• Attaches to the skeleton via tendons

• Lines the stomach and intestines

• Composes the walls of the heart

Multiple Choice

The only voluntary muscle tissue that produces bodily movement

• Cardiac muscle

• Smooth muscle

• Skeletal Muscle

Introduction to skeletal muscle

• Under voluntary control​ of the nervous system

• Accounts for 36%-45% of the total body weight

• Over 650 different muscles

• Most plentiful tissue in the human body​

Introduction to skeletal Muscle cont...

To enable the body to move, the muscles usually work together in muscle groups.

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Most of the muscle groups in the trunk and extremities work in opposing pairs​

​The "opposite muscle"

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This muscle is the one that is being stretched while the agonist contracts.​

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Antagonist Muscle

The muscle that is initiating the desired movement.

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The "Main Mover"​

​Agonist muscle

Agonist and Antagonist

During a bicep curl, the main movement is flexion of the arm. This is achieved by the ​contraction of the bicep.

Biceps

​While the bicep is contracting the tricep is relaxing and stretching. ​

Triceps

Example of Agonist vs antagonist

Open Ended

Can you try to name another pair of muscles that are agonist and antagonistic to each other?

Multiple Choice

How many skeletal muscles are in the body

• 206

• 405

• over 650

• over 1000

Multiple Choice

Which is considered the "main mover"

• Agonist muscle

• Antagonist muscle

• Smooth muscle

• Cardiac muscle

Multiple Choice

What type of muscle is considered the opposing muscle during a given movement

• Agonist muscle

• Antagonist muscle

• Smooth muscle

• Cardiac muscle

Match

Match the agonist muscles with their antagonist muscle

• Bicep

• Quadricep

• Latissimus Dorsi

• Gastrocnemius

Tricep

Hamstring

Pectorals

Tibialis Anterior

• Tricep

• Hamstring

• Pectorals

• Tibialis Anterior

Muscle Actions

Neural stimulation can lead to three types of muscle actions

1. Concentric action

2. Eccentric action

3. Isometric action​

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Concentric action

• ​This occurs when a muscle shortens in order to overcome a load

• For example, the bicep muscle experiences concentric action during the upward phase of a bicep curl.

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Subject | Subject

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• This occurs when the muscl​e is overcome by a load and is forced to lengthen

• This occurs during the downward motion of a bicep curl.​

• Can also be thought of as the ​deceleration of joint motion

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Eccentric Action

• Occurs when a muscle generates force against a resistance but no movement takes place.

• Think of flexing a muscle and holding it.

• Many postural muscles fire isometrically to keep the body upright.​

Isometric Action

Match

Match the following

• Concentric contraction

• Eccentric contraction

• Isometric contraciton

Muscle shortens

Muscle lengthens

Muscle does not shorten or lengthen

• Muscle shortens

• Muscle lengthens

• Muscle does not shorten or lengthen

Subject | Subject

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​Muscle Fiber types

• ​There are two types of muscle fibers

• Fast twitch (Type II) and slow twitch​ (Type I)

• Fiber types are differentiated by their metabolic and contractile properties​

Fast Twitch (Type II)

• Fast twitch fibers have the ability to generate rapid, powerful muscle actions.

• Type II fibers' speed of shortening is three to five times faster than that of slow twitch.

• Predominately used in anaerobic movements such as, volleyball spike or a tennis serve.​

• These fiber types tend to fatigue easily.​

Subject | Subject

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Slow Twitch (Type I)

• These fiber types are typically involved in energy production for prolonged aerobic activities.

• For example, aquatic exercise, long distance running, and stationary cycling will all involve the use of slow twitch muscle fibers.

• These are described as fatigue resistant​.

Subject | Subject

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Fast Twitch vs. Slow twitch

Multiple Choice

Which of these activities would require predominately Fast twitch muscle fibers

• Running a Mile

• Cycling

• Swimming

• 100m dash

Multiple Choice

Which of these activities would require predominately slow twitch muscle fibers

• Volleyball spike

• Tennis serve

• 100m dash

• Marathon

Open Ended

Tell me the most interesting thing you learned about muscles.

SKIN aka the integumentary system

Integumentary System

Middle School

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Learning Objectives

• Identify the primary functions and main structures of the integumentary system.

• Describe the three main layers of the skin: the epidermis, dermis, and hypodermis.

• Differentiate between the specialized cell types found in the epidermis.

• Explain the roles of accessory structures, including hair, nails, and glands.

Key Vocabulary

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Epidermis

The outermost, avascular layer of the skin that provides a tough, protective barrier from the environment.

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Dermis

The layer of skin below the epidermis, containing nerves, blood vessels, and other accessory structures.

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Keratin

A durable, waterproofing protein that fills cells in the epidermis, providing both strength and protection.

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Melanin

A pigment that determines skin color and helps to absorb harmful ultraviolet (UV) light from the sun.

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Hypodermis

The subcutaneous layer of fat and connective tissue below the dermis that anchors the skin.

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The Integumentary System: An Overview

• The integumentary system is the body's largest organ system.

• It includes the skin, hair, nails, sweat, and oil glands.

• This system protects the body and helps retain essential fluids.

• It also regulates temperature and helps produce vitamin D.

Multiple Choice

Which of the following is NOT a primary function of the integumentary system?

• Regulating body temperature

• Protecting the body from bacteria

• Producing digestive enzymes

• Eliminating waste products

The Three Main Layers of Skin

• The epidermis is the outermost avascular protective layer of the skin.

• The dermis is the middle layer containing nerves and blood vessels.

• The hypodermis is the deepest layer, made of fat and connective tissue.

Multiple Choice

Which layer of the skin is avascular, meaning it does not contain blood vessels?

• Dermis

• Hypodermis

• Epidermis

• Reticular Layer

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Specialized Cells of the Epidermis

• Keratinocytes produce keratin, a protein that makes skin tough and waterproof.

• Melanocytes produce melanin, which gives skin color and absorbs harmful ultraviolet (UV) light.

• Langerhans cells are immune cells that help fight off germs entering the skin.

• Merkel cells are touch receptors that allow you to feel a light touch.

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Multiple Choice

Which type of cell in the epidermis is responsible for producing the pigment that gives skin its color?

• Keratinocytes

• Merkel Cells

• Langerhans Cells

• Melanocytes

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Accessory Structures of the Skin

Hair and Nails

• Hair is made of protein and grows from follicles in the dermis, providing insulation and sensory input.

• Nails are composed of a nail plate, nail bed, and cuticle, which protect our fingers and toes.

• These structures also assist with fine motor skills like gripping objects and enhance the sense of touch.

Exocrine Glands

• These glands release substances to the skin's surface through ducts to perform specific functions in the body.

• Sweat glands regulate body temperature, while sebaceous glands produce oil to waterproof the skin and hair.

• Ceruminous glands are found in the ear canal and are responsible for producing protective earwax.

Multiple Choice

What is the primary function of sebaceous glands?

• To produce sweat for cooling

• To produce protective earwax

• To produce oil to keep hair soft

• To form the nail plate

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Common Misconceptions

Misconception	Correction
The skin is just a simple outer covering.	The skin is a complex organ, the largest in the body.
Only the top layer of skin matters.	All layers of skin are crucial for sensation and temperature regulation.
Hair and nails are just dead structures.	Hair and nails are important for protection and sensation.

Multiple Choice

How do the sebaceous glands and hair follicles work together as part of the integumentary system?

• They both work together to produce sweat.

• The gland cools the hair to prevent overheating.

• The gland secretes oil into the follicle to soften and protect the hair.

• The follicle produces wax which is stored in the gland.

Multiple Choice

Why is the dermis considered the 'vasculated' area of the skin, and how does this property relate to its function?

• It has no blood vessels and primarily stores fat for insulation.

• It has many nerves for touch but lacks a blood supply.

• It contains blood vessels that supply nutrients and help regulate body temperature.

• It contains all the melanin for UV protection, which requires blood flow.

Multiple Choice

A person has a genetic condition that prevents their keratinocytes from producing enough keratin. What would be the most likely consequence for their skin?

• Their skin would lose its color and pigmentation.

• Their skin would become less able to sense touch and pressure.

• Their skin would be less waterproof and more prone to damage and infection.

• The immune response within their skin would be significantly weaker.

Multiple Choice

Considering the functions of the integumentary system, predict two ways the system would react if you moved from a cold, dry climate to a hot, humid one.

• Sebaceous glands would stop producing oil, and sweat glands would become inactive.

• Sweat glands would increase sweat production, and melanin production would decrease.

• Sweat gland activity would increase, and blood vessels in the dermis would dilate to release heat.

• Hair follicles would produce thicker hair, and the epidermis would get thinner to release heat.

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Summary

• The integumentary system includes the skin, hair, nails, and glands.

• It protects, regulates temperature, retains fluids, and produces vitamin D.

• The skin has three main layers: the epidermis, dermis, and hypodermis.

• Hair, nails, and glands are accessory structures with protective and sensory functions.

Multiple Choice

Which of these is NOT a function of the skin?

• acts as a layer of protection against germs

• circulates blood through the body

• regulates body temperature

Multiple Choice

What is the top layer of the skin called?

• epidermis

• dermis

• subsurface

​FUNCTIONS:

• It protects the body’s internal living tissues and organs.

• It protects the body against microorganisms and invasion by infectious organisms.

• It helps dispose of waste materials.

• It acts as a receptor for touch, pressure, pain, heat, and cold.

• It stores water and fat.

• It helps in the production of vitamin D.​

Science and Health 6​

​Structure of the skin:

• The skin is the main organ of the “integumentary system”.

• SKIN is composed of four types of tissues:

  Epithelial Tissues, Connective Tissues, Muscles Tissues  Nerve Tissues

Science and Health 6​

​Epidermis

​▪outer layer of the skin

▪consists of epithelial cells

▪The outer layer of epidermal cells contains protein called “KERATIN” which water proofs and protects the cells and tissues that lie underneath.

Science and Health 6​

​Dermis

​▪second layer of the skin

▪directly between the epidermis and the subcutaneous layer

▪usually 15 to 40 times thicker than the epidermis.

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Science and Health 6​

​Dermis

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▪consists of connective tissues that prevent the skin from tearing and enables the skin to return to it’s normal state after being stretched.

▪contains structures including nerve cells, muscle fibers, sweat glands, oil glands, and hair follicles

Science and Health 6​

​Hypodermis layer

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▪layer of connective tissue that stores fats and helps the body retain heat.

Science and Health 6​

​HAIR

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▪threadlike outgrowths from the follicles that are found in the dermis

▪made up of keratin and melanin

▪keeps dusts, insects and other unwanted things out of the body

Science and Health 6​

​NAIL

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▪hard, thin covering on the upper surface of the ends of the fingers or toes

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▪made of keratin

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▪ The fingernail generally serve two purposes:

-serves as a protective plate

- enhances sensation of the fingertip

Science and Health 6​

Multiple Choice

The top layer of the skin is called the _________________.

• dermis
• oil gland
• nerve
• epidermis

Multiple Choice

What are the three main layers of the skin?

• The epidermis, the dermis, and the hypodermis

• The epidermis, the dermis, and the sebaceous
• The dermis, the sebaceous, and the sudoriferous
• The sudoriferous, the dermis, and the epidermis

Multiple Choice

The coloring in the skin; found in the epidermis.

• Melanin
• Oil
• Perspiration
• Pores

Multiple Choice

The waterproofing protein that fills the cells in the upper layers of the epidermis.

• Keratin
• Melatonin
• Melanin
• Actin

Multiple Choice

What gland is responsible for keeping our hair soft and is a barrier for bacteria and fungi?

• Sudoriferous
• Sebaceous
• Melanin
• Carotene

Multiple Choice

What is the name of tube that our hair grows from?

• Follicle
• Root
• Shaft
• Sebaceous

Multiple Choice

Which layer contains accessory structures such as sweat glands, sebaceous glands, and hair follicles?

• epidermis
• dermis
• hypodermis
• hyperdermis

Multiple Choice

Which layer of the skin does NOT contain blood vessels? 

• epidermis
• hypodermis
• dermis

Multiple Choice

Which are part of the integumentary system?

• Muscles, skeleton, bone marrow

• Hair, skin, bones

• Hair, skin, nails

• Brain, spinal cord, nerves