BIOB34H3 Lecture Notes - Central Tendon Of Diaphragm, Rhomboid Muscles, Extraocular Muscles

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greenherring451

15 Dec 2012

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The skeletal muscle of the body can be subdivided into: Muscles that position the head and vertebral column. Muscles that stabilize or move the appendicular skeleton. The axial muscles can be placed into four groups based on location or function. Muscles of facial expression (mouth, eye, nose, scalp, neck) Masseter elevates mandible and closes aws, assists in protracting nd retracting mandible and moving mandible from side to side (for mastication) Temporalis elevates mandible and closed jaws, assists in retracting and moving mandible from side to side (right over the temporal bone) Medial pterygoid elevates the mandible and closes the jawa, or moves the mandible side to side. Lateral pterygoid opens jaws, protrudes mandible, or moves mandible side to side. Muscles of the pharynx (pharyngeal constrictors, laryngeal elevators, palatal muscles) Digastric depresses mandible, opening mouth, and/or elevates larynx. Sternocleidomastoid together they flex the neck, alone one side bends neck toward shoulder and turns face to the opposite side.

Related Questions

1. Consider the following eight statements about vertebrae. Which four of the following eight statements are TRUE? Choose all four correct answers.

(a) In Actinopterygii, Chondrichthyes, and some Amphibia (and one unusual taxon of Lepidosauria), the vertebrae have centra which surround the notochord.

(b) Some vertebrae have processes such as spines that function as sites for muscle attachment.

(d) In tetrapods, the vertebrae have processes called zygapophyses that function as specialized sites for articulation with the ribs.

(e) Vertebrae arise from sclerotome epimere mesoderm.

(f) All extant vertebrate taxa have vertebrae.

(g) Some vertebrae have hemal arches which protect blood vessels (such as the dorsal aorta).

(h) Vertebrae have neural arches which protect the notochord.

2. While walking through the halls of the Biosciences building, you find a single vertebra lying on the floor. You notice that it does not have zygapophyses. It has an amphicoelous centrum, and it has both a neural arch and a hemal arch. This vertebra is completely ossified. Identify to which vertebrate taxon this vertebra belongs, and to which region of the vertebral column.

(a) caudal region - Petromyzontida

(b) thoracic region - Aves

(d) trunk region - Actinopterygii

(e) caudal region - Actinopterygii

(f) caudal region - Amphibia

(g) caudal region - Chondrichthyes

3. You are doing a study on the diet of polar bears. While examining the scat (droppings) of a large polar bear, you find a single vertebrae. You need to identify this vertebra to determine what this polar bear has been eating. Polar bears are known to eat mammals, birds, and some fish (Actinopterygii). This vertebra has a heterocoelous centra and it has no articulation sites for ribs. It also has an odontoid process. To which of these three vertebrate taxa, and to which region of the vertebral column does this vertebra belong?

(a) synsacral region - Aves

(b) cervical region - Mammalia

(d) cervical region - Aves

(e) caudal region - Actinopterygii

(f) thoracic region - Mammalia

4. Which four of the following eight statements about the skeleton are TRUE? (Choose all four correct options.)

(a) Bone is a tissue that is able to withstand large tensile forces but not large compressive forces.

(b) An important role of the vertebral column in actinopterygii and chondrichthyes is to support the body weight.

(c) in amniotes, the ribs consist of two parts, a costal rib (which articulates with a thoracic vertebra) and a sternal rib (which articulates with the sternum). The mobile joints between the costal and sternal rib, as well as between the costal rib and the vertebra and between the sternal rib and the sternum, make the ribcage flexible such that it can expand during breathing.

(d) A vertebral column with procoelous centra would have a greater range of mobility than a vertebral column with acoelous centra.

(e) In all extant vertebrate taxa, the vertebral column provides axial structural support, as well as support for locomotion.

(f) In many mammals, ligaments and muscles attaching to the neural spines of vertebrae help to stabilize the vertebral column and pull it into a stable arch, which helps to efficiently bridge the body weight to the legs.

(g) In tetrapods, the pectoral girdle is firmly fused to the vertebral column to allow for efficient transfer of locomotive forces from the forelimbs to the axial skeleton.

(h) In chondrichthyes, actinopterygii, sarcopterygii, and some tetrapods, the vertebral column acts as a firm but flexible rod on which muscles pull to produce lateral undulations of the body for locomotion.

5. Consider the following eight statements about the form and function of the appendicular skeleton. Which four of the following eight statements are TRUE? (Choose all four correct options.)

(a) In sharks (Chondrichthyes), the pectoral and pelvic fins are mainly used for propulsion - to propel the body forward through the water.

(b) The tips of fins are supported by fin rays, thin rods which support a webbing of skin (and sometimes also connective tissue) - this increases the surface area of the fin

(c) The fleshy fins of sarcopterygii are not very maneuverable, and are used only to stabilize the body by preventing roll, pitch, and yaw when swimming rapidly.

(d) In both actinopterygii and chondrichthyes, the pectoral girdle attaches directly to the back of the skull while the pelvic girdle is embedded in the muscle of the body wall.

(e) In both sharks (Chondrichthyes) and actinopterygii, the pectoral and pelvic fins provide stability while swimming by preventing roll, pitch, and yaw.

(f) In male chondrichthyes, the pelvic fins have special extensions called claspers that are used to transfer sperm to females during copulation for internal fertilization.

(g) Petromyzontida and myxinoidea have paired pectoral and pelvic fins that are used to provide stability while swimming, as well as for steering.

(h) The main functions of girdles are to provide attachment sites for the muscles of the appendages (paired fins or limbs) and to stabilize the appendages.

6. Consider the following statements related to the appendicular skeleton and terrestrial locomotion of tetrapods. Which three of the following six statements are CORRECT? (Choose all three correct options.)

(a) In tetrapods with erect limb posture, the limbs are positioned directly under the body, while in tetrapods with sprawled limb posture, the limbs are positioned to the sides of the body.

(b) In terrestrial tetrapods, the distal ends of the humerus and femur are rotated such that the digits are oriented in line with the direction of travel, increasing both tractive and propulsive forces during terrestrial locomotion.

(c) Tetrapods with digitigrade foot posture have relatively longer limbs than tetrapods with plantigrade foot posture, such that they have a greater stride length.

(d) When terrestrial tetrapods are walking or running, the recovery stroke of the limbs involves the limb touching the ground while the propulsive stroke of the limbs involves the limb being lifted and moving from posterior to anterior.

(e) In tetrapods with sprawled limb posture, the dorsal elements of the pectoral girdle (such as the scapula) are much larger than the ventral elements of the pectoral girdle (such as the clavicle and corocoid).

(f) When walking or running, tetrapods with erect limb posture use an overarm swing for the recovery stroke, which is relatively slow.

7. You are walking along the beach and find a skeleton in the sand. You notice that the pelvic girdle is not fused to the vertebral column while the pectoral girdle is fused to the skull. The distal ends of the appendages have fin rays. It appears that all muscles controlling the appendages were located within the body wall, not within the appendages. To which vertebrate taxon does this skeleton belong?

(a) Sarcopterygii

(b) Lepidosauria

(d) Amphibia

(e) Actinopterygii

(f) Petromyzontida

8. Your neighbour finds a skeleton while cleaning out the pond in her backyard, and she asks you to identify it. You notice that the vertebrae have zygapophyses and that the centra of the vertebrae are procoelous. The ribs are quite short, and articulate with the vertebrae but not with the sternum. The pelvic and pectoral girdles appear robust and highly ossified, and the pectoral girdle has enlarged ventral elements but relatively small dorsal elements. The appendages each have five digits. Identify this skeleton for your neighbour, and describe to her as much as you can about its style of locomotion, based on this information about its axial and appendicular skeleton. (Choose all three correct options.)

(a) This skeleton is most likely from an amphibian.

(b) This skeleton is most likely from a sarcopterygian.

(d) This animal most likely had sprawled limb posture.

(e) This animal most likely could not support its own body weight using its appendages, and so would not have been capable of terrestrial locomotion.

(f) This animal probably walked with lateral undulations of the body, using the feet as pivot points.

(g) This animal most likely walked with a recovery stroke that used an energetically efficient pendulum-like swing.

(h) This skeleton is most likely from a crocodilian (Archosauria).

Jim, A 19-year-old college student, was rock climbing when he fell 30 feet to the ground. Paramedics arriving at the scene found him lying in the supine position, unable to move any extremities and complaining of neck pain. He was awake, alert, and oriented to his current location, the date and day of the week, and the details of his fall. His responses to questioning were appropriate. He complained that he could not feel his arms and legs. His pupils were equal and reactive to light. He showed no other signs of injury except for several scrapes on his arms. His vital signs revealed a blood pressure of 110 / 72, heart rate of 82 beats per minute, respirations of 18 per minute. The paramedics applied a cervical collar, placed him on a back board, immobilized his head, and transported him to the trauma center by helicopter. Upon examination at the hospital, Jim had minimal biceps brachii stretch reflexes, but no triceps or wrist extensor reflexes. All other muscle stretch reflexes in the upper and lower extremities were absent. His perception of sensory stimuli ended bilaterally at an imaginary line drawn across his chest about 3 inches above the nipples (i.e. everything below felt numb). He had some sensation in his arms, but could not localize touch or describe texture with any consistency there. He was able to raise his shoulders and tighten his biceps brachii slightly in each arm, but could not raise either arm against gravity. His lower extremities were flaccid, despite attempts to move them. Vital signs were taken again at the hospital and were as follows: blood pressure=94 / 55; heart rate=64; respiratory rate=24 (with shallow breathing). X-rays taken upon arrival revealed a fractured vertebra at a particular location. A chest X-ray showed a decreased lung expansion upon inhalation. The neurosurgeons immobilized his neck by inserting tongs into the skull above the ears to hold his neck in a position so that no further injury could occur. Jim was transferred to intensive care and his condition was stabilized. A physical examination four days later revealed normal vital signs and no change in his arm strength or sensation, but also marked spasms and exaggerated stretch reflexes of the lower extremities. He also had urinary incontinence which required the placement of a Foley catheter connected to a urine collection bag.

Questions:

1. Why did Jim's heart rate and blood pressure fall in this time of emergency (i.e. at a time when you'd expect just the opposite homeostatic responses)?

2. Upon admission to the hospital, Jim's breathing was rapid and shallow. Can you explain why?

3. Why did he lose some sensation in his arms and all sensation from the upper trunk down?

4. What is the primary muscle of respiration? Which spinal nerves contribute to innervate this muscle? (Itâs almost like this question is reviewâ¦)

5. Based upon the physical exam findings, which vertebral bone do you think was fractured? Give reasons for your answer. (Lifeâs anatomy knowledge is cumulativeâ¦)

6. By four days after the injury, some of Jim's signs and symptoms had changed. His arm muscles were still flaccid, yet his leg muscles had become spastic and exhibited exaggerated stretch reflexes. How would you explain these findings?

Background

Almost all animal and plant cells require oxygen and give off carbon dioxide. This is called gas exchange and it occurs by passive diffusion. Some animals do all or most of their gas exchange across their skin (for example amphibians) but they have very low metabolisms and use very little oxygen and get rid of very little carbon dioxide.

On the other hand humans (and other mammals) have very high metabolic requirements and we canât rely on gas exchange over the limited 1.5 to 2.0 square meters of our skin to get enough oxygen in and carbon dioxide out fast enough. Our gas exchange takes place across a very thin membrane in the Alveoli of the lung and the gas exchange surface in humans is estimated to be between 50 and 100 square meters, or between 25 and 67 times our skin surface area.

Our lungs provide a huge surface for gas exchange but they are a dead-end system. Once the oxygen in the lungs is used up it needs to be replenished and carbon dioxide builds up in the air spaces in the lungs and needs to get out. This is where the diaphragm and a few of the skeletal muscles become important. In its relaxed state the diaphragm is at its longest and the space in the thoracic cavity (and the lungs) is small. When the diaphragm contracts it shortens, which increases the volume of the thoracic cavity (and the lungs). The increase in size means the pressure is lower in the lungs than outside so air comes into the lungs (inhalation). As the diaphragm relaxes, the lungs decrease in size enough that the pressure inside the lungs is higher than the external air pressure so air comes out (exhalation).

Introduction

In this lab you will be building a model of a lung and experimenting with different ways to breath.

Supplies:

In the Lab Kit

One round 9" balloon (one lung, we donât need two for this)
medium-sized plastic bag large enough to fit over bottom end of bottle (diaphragm)
medium-size, thin rubber band

You supply

plastic 2-liter soda bottle with bottom cut off (thoracic cavity)

Tape (optional)

Directions:

1. Insert the balloon through the open bottom of a modified 2-liter soda bottle and up over the neck of the bottle. Pull the end of the balloon over the edges of the neck of the bottle. The balloon is held open by the neck of the bottle.

2. Place the plastic bag over the bottom (open) end of the 2-liter bottle and use the rubber band to hold it in place. This will serve as the diaphragm. To inflate the lung, blow into the balloon just before you fasten the rubber band. You can also wrap tape over the edges of the plastic bag to minimize air leaks

3. Grasp the bottom of the plastic bag and pull it down and push it up. Watch as the "lungs" (the balloon) expand and contract as you do this. The balloon has to change size because the air space between the balloon and bottle must remain constant. (Well, it would if the seal around the plastic bag and bottle were perfect).

You may block the "trachea" (the neck of the bottle) so that the air supply is cut off and watch as nothing happens when the "diaphragm" is pushed in and out.

This model isnât perfect. None of the joints are air tight as they would be in a real thoracic cavity. Pull the âdiaphragm down and watch the lungs expand . If you hold it in place, the lungs will collapse again over time. This is because of leaks and is not how real lungs work. Pushing the diaphragm in and pulling it out over and over does give you an idea of how lungs work. As the diaphragm tightens, contracts (pull down on the plastic bag) the lungs fill with air. As the diaphragm relaxes (push up on the plastic bag) air is expelled from the lungs .

There are several different ways we breath, i.e. expand our thoracic cavity so that our lungs can expand. You have just made a demonstration model of the diaphragm at work. You can also use your rib cage to expand and contract so that you can inhale and exhale. There are muscles between and around your ribcage which you can use to change the size of your thoracic cavity.

This is approximately what your model of a lung will look like.

Answer the questions on the Report Page

Report Page Name

1. Put a hand on your lower ribcage and try moving your ribs out and in. Does air also move in and out?

2. Someone with an upper back or neck injury may not have the options of using diaphragm or ribs to breath. They can learn to use the clavicle and the muscles attached to expand their thoracic cavity a small amount and breathe independently for short periods of time. Put your hand on you clavicle and try to raise and lower just that bone without using your diaphragm or your ribs. It isnât easy but you should be able to get a little air into and out of your lungs this way. How effective do you think this way of breathing is?

3. When you take a really deep breath you use all these muscle groups to help. Take a really deep breath and notice that your ribs expand, your lower abdomen comes out (a sign that the diaphragm has contracted) and your shoulders lift a little (the upper chest and clavicle are working). Now take a relaxed breath. Only your abdomen should go in and out. The movement of your abdomen is a result of the contracting diaphragm pushing on the contents of your âgutâ which forces your abdomen to push out.

Do you breath in or out when your diaphragm contracts?\

4. If a hole were poked in your thoracic wall (the wall of the pop bottle â the hole should be at least the diameter of a pencil)

a. what would happen when you tried to breath? (This is a pneumothorax).

b. Is the space between the balloon and plastic bottle still required to remain constant?

5. Would it be possible to live with a paralyzed diaphragm? Explain your answer.

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BIOB34H3 Lecture Notes - Central Tendon Of Diaphragm, Rhomboid Muscles, Extraocular Muscles

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