Anatomy Unit 2 Test Study Guide

Our muscles can act with our bones to form lever systems. The lever system that allows a bicep curl would be considered a _________ and the lever system that allows you to lift your head from your chest would be considered a ____________ .

3rd class lever; 1st class lever

Explain why people who experience paralysis in their lower limbs have thinner, weaker bones in their legs and thighs.

Because bone remodeling is stimulated when the osteocytes receive signals, such as stress/force being put on the bones, to rebuild the bone. If these stimuli are not sent that bone will not be regenerated and strengthened.

Explain why there is an abundance of mitochondria in our muscle cells.

Because cellular respiration occurs in the mitochondria and muscle contractions require lots of energy so our muscle cells need to be able to constantly breakdown sugars for ATP, when needed.

Why are some ribs classified as "floating"?

Because the last two pairs of ribs are only attached posteriorly to the vertebrae and not anteriorly to the sternum

Why is the nervous system critical for muscle contractions?

Because they are skeletal muscles only contract voluntarily and excitable cells, so they must be signaled by the nervous system to be stimulated.

Which of the following anatomical characteristics is not shared by all synovial joints?

C. fibrocartilage

Place the following steps of the bone remodeling process in the correct order. (4 pts) A. Osteoclasts return calcium and phosphate to the blood through resorption. B. Macrophages promote bone tissue remodeling. C. Osteoblasts come in and build new bone. D. Osteocytes release chemical signals to send osteoclasts to the damage.

D → A → B → C

What two things must be obtained in order for a muscle contraction to occur?

Energy from ATP and access to the actin (so myosin can bind)

Refer to the figures below. Which is showing a female pelvis? Include two reasons to support your answer.

Figure A is showing a female pelvis because the pubic arch is wider and the wider space around the sacrum provides for a birth canal, both of which accommodate for females to grow and birth an infant.

A bone that has a large surface area, specifically for muscle attachment.

Flat bone

Joints can be immovable, slightly movable, and freely movable. Describe one benefit of each type and include an example of where each exists in the human body.

Immovable joints offer the most stability. Ex. The joints (sutures) in your cranial bones that protect your skull. Freely movable joints offer the most flexibility and maneuverability. Ex. The joints in your knee and elbow that provide a lot of movement in our limbs. Slightly movable joints have benefits of both - they offer some flexibility while still being very stable.

List three ways muscles can increase the force of their contraction.

Increase Increase the the trapezius deltoid latissimus dorsi erector spinae gluteus maximus sartorius gastrocnemius frequency of motor neuron (and thus motor unit) stimulation number of motor units (and thus muscle fibers) stimulated Increase the size of the muscle fibers so that more tension can build up

One function of the muscular system is to help regulate constant body temperature. Explain how this system contributes to maintain homeostasis in this way.

Muscle contractions need lots of energy from ATP,

Summarize the sliding filament model. Refer to the diagrams below in your summary.

Muscles contract because sarcomeres contract. Sarcomeres contract when the heads of myosin filaments can grab the thinner actin filaments and pull them to slide past each other. This causes the filaments to overlap more (see the disappearing H zone in Figure B) and the sarcomere to shorten (see the Z discs closer together in Figure B than in Figure A)

List four of the six overall functions of the skeletal system we discussed in class.

Support/framework for the body, protect/guard organs, aid in movement, storage of minerals and energy, blood cell formation (hematopoiesis), hormone production

Allows for the most maneuverability of all the joints.

ball and socket

Which of the following is the main muscle of the cheek?

buccinator

Which of the following places the regions of the vertebral column in the correct order, starting in the neck?

cervical -> thoracic - lumbar - sacral - coccyx

On the figure on your answer sheet, label the bones indicated by the lines using the word bank provided.

clavicle scapula humerus ulna radius carpals metacarpals phalanges

Which of the following is not considered to be part of the axial skeleton?

coxal bones

The prime mover in inspiration is the

diaphragm.

Connect bones with collagen fibers.

fibrous

Joints in the cranial bones of the skull.

fibrous

Nearly all are functionally classified as synarthrotic.

fibrous

Which of the following leg bones doesn't actually bear any weight but instead aids in stabilizing the ankle joint?

fibula

The quadriceps are the prime movers in extension and are antagonized by the

hamstrings.

Pictured to the right.

hinge

A bone with a highly specialized shape and structure, like the coxal bones.

irregular bone

The type of bone pictured to the right.

irregular bone

The type of bone that most of the limb bones can be classified as.

long bone

The endomysium is the connective tissue that surrounds each

muscle fiber

The ______ are the muscle cells, containing specialized organelles called ____________ .

muscle fibers; myofibrils

The girdle provides more flexibility and motility than the girdle. The girdle is the sturdiest of the two.

pectoral; pelvic; pelvic

Allows for supination and pronation.

pivot

Makes your thumb opposable.

saddle

A bone that has approximately the same width, length, and height.

short bone

The bones in your wrist.

short bone

All are functionally classified as diarthrotic.

synovial

Has a fluid-filled cavity.

synovial

Shoulder, hip, jaw, and elbow joints.

synovial

The bones that make up the ankle are known as the

tarsals

Cords of dense connective tissue that connect muscles to bone are called

tendons

A contraction caused by a single brief stimulus is known as a

twitch.

On the figure on your answer sheet, label the muscles indicated by the lines using the word bank provided.

which comes from cellular respiration. This is an overall exothermic reaction so a byproduct of it is heat!