Human Biology N-16 Human Biology N-16 ANATOMY – The Muscular System

Types of Muscle In the Human Body there are 3 different types of muscle. These are: SMOOTH – Also known as INVOLUNTARY muscles. Found in the internal organs such as the intestine. They are named as such because we do not have conscious control over them. CARDIAC – Found only in the heart. We cannot control it and it is constantly working. It enables blood to be pumped from the heart to the body. SKELETAL – Often called VOLUNTARY muscle. It enables us to move and is under our conscious control.

The Major Muscle Groups

Function and Movement of Major Muscles Biceps - Biceps - Flexes your arm at the elbow.

Function and Movement of Major Muscles Triceps – Triceps – Extends your arm at the elbow joint. Tricep

Function and Movement of Major Muscles Deltoid - Deltoid - extends your arm at the shoulder.

Function and Movement of Major Muscles  Abdominals -  Abdominals - Flex the spine so you can bend forward.

Function and Movement of Major Muscles  Pectorals -  Pectorals - Flexes your arm at the shoulder. Draws it across your chest.

Function and Movement of Major Muscles Latissimus Dorsi (lats) - Latissimus Dorsi (lats) - Flexes your arm down at the shoulder. Draws it behind your back.

Function and Movement of Major Muscles Trapezius - Trapezius - Flexes and rotates your shoulders. Moves your head back and sideways.

Function and Movement of Major Muscles Quadriceps - Quadriceps - Extends the leg at the knee and keeps it straight when you stand.

Function and Movement of Major Muscles  Hamstrings –  Hamstrings – Flex your leg at the knee.

Function and Movement of Major Muscles  Gluteals -  Gluteals - Extension at the hip.

Function and Movement of Major Muscles  Gastrocnemius –  Gastrocnemius – Plantarflexion of the ankle joint (standing on your tiptoes).

How the Muscles Move Muscles are attached to two different bones (across a joint) by tendons. When the muscle contracts only one bone moves. The place where the muscle is attached to the stationary bone is called the ORIGIN. The place where the muscle is attached to the moving bone is called the INSERTION.ORIGININSERTION

How the Muscles Move Cont’d To make a joint move in two directions, you need two muscles that work in opposite directions. ANTAGONISTIC muscles are pairs of muscles that work against each other. One muscle contracts. This is called the AGONIST or PRIME MOVER. The other one relaxes. This is called the ANTAGONIST Remember what ANTAGONISTIC PAIRS Do!!!!!

Muscles for Endurance and Power Muscles are made up of lots of individual fibres. In skeletal muscle, these fibres are either FAST TWITCH or SLOW TWITCH. Both have their different roles … Fast twitch for power, slow twitch for endurance. Fast twitch fibres contract very quickly and powerfully, but they get tired fast. They are useful for explosive, short duration activities sprinting and weightlifting.

Muscles for Endurance and Power Slow twitch fibres contract more slowly and with less force, but they don't get tired as quickly. They are useful for endurance activities. Everyone has a similar number of muscle fibres, but it is the proportion of fast twitch to slow twitch fibres that differs. You cannot change the amount of slow or fast twitch muscle fibres that you have, but you can train them to work more effectively.

The Effect of Exercise and Training on Muscles Skeletal muscle responds to training and exercise (or lack of it) in two ways. Regular training and exercise can create greater muscle development (HYPERTROPHY). Too much inactivity causes muscle wastage (ATROPHY)

The Effect of Exercise and Training on Muscles When we exercise our bodies regularly and with heavy workloads (normally ANAEROBIC), muscle fibre size increases until the muscle has become large and strong enough to do the tasks required of them. Carrying heavy, bulked muscle does not help endurance athletes so the muscles adapt to using the energy efficiently, and normally will only grow to the maximum size that they need to be.