Animal Support, Movement and Locomotion P.1

Animal Support, Movement and Locomotion

Support is the maintenance of the body in particular sh____ and pos_____. Some means of support is needed to prevent the body from collapse due to the pull of g______.

Movement of the whole organism from place to place is termed locomotion. Plants exhibit cellular and often organ movement, but they do not exhibit locomotion, that is they don’t move from place to place.

Q1. What is the name given to animals that remained attached to one place ?

Q2.Suggest five reasons for animals to move from place to place ?

I)Support and movement on land and water

Land
(terrestrial animals) / Water
(aquatic animals)
Support offer by medium / Air offer little s______ due to its low density
Land animals need a relatively st______skeleton to l___ the body off the ground. Otherwise fric_____ would not allow the animals to move freely.
Size of terrestrial animals are limited by their body w______/ Water provide very good support against gravity due to its high den_____
Skeleton is adapted not for support against gravity but for maintaining s______and for p______against injury.
Aquatic animals tend to be larger due to better support from bu______of water
Resistance to movement / less / More. Aquatic animals often are st______in shape to reduce res______in water.

II)Skeletal Systems

Three major types of skeleton are generally recognised: hydrostatic, exoskeleton and endoskeleton.

III)The general functions of skeleton:

1)Support. All skeletons provide a rig__ framework for the body. They help to maintain the sh___ of the body. Within the body, org___ are attached to, and suspended, from the skeleton.

2)Protection. The skeleton protects the delicatein______organs in those organisms with an exoskeleton (arthropods), and parts of the endoskeleton are designed for a similar function. For example, in humans the cran_____ protects the brain and the sense organs of sight, smell, balance and hearing; the v______column protects the spinal cord, and the r___and st_____ protect the heart, lungs and large blood vessels.

3)Locomotion. Skeletons composed of rigid material provide a means of att______for the muscles of the body. Parts of the skeleton operate as lev___ on which the muscles can pull. When this occurs, movement takes place.

4)Production.Red bone m______ in the spongy bone is the site of production of blood cells

5)Storage. Yellow bone marrow store f___. The skeleton serves as a res______of calcium. The amount of calcium in bones may be released for metabolic uses (e.g. blood clotting, proper functioning of muscles and nerves) when bl_____ calcium is low and vice versa.

IV)Endoskeleton

Thevertebrates skeleton is an in_____ supporting frameworkinsidethe body, it is therefore refers to as an e______. It is made either of c or b tissue. Only cartilaginous fish (such as dogfish and sharks) possess a whole cartilaginous endoskeleton. All other vertebrates have a b____ skeleton in their adult form, but with cartilage also present in certain regions, such as at the joints or between the vertebrae.

Unlike exoskeleton in arthropod, endoskeleton is composed of l tissue and so can g_____ steadily with the animal thus avoiding the need for moulting.

Places where bones meet arej . Bonesat joints are maintained in their correct relative position by elastic l .

V)Skeletal tissues

a)Cartilage

  • at the ends of long bones articulating to form j_____.
  • as discs between v______and
  • in the ear f____, epiglottis and pharyngeal cartilages.

It is compr and el , and is well able to withstand heavy w_____ and absorb mechanical sh . Within the matrix are embedded fine collagen fibres which provide t______strength.

b)Bone

  • Bone is a hard, tough connectivetissue. It contains l______cells which are embedded in a firm, calcifiedmatrix.
  • Bone matrix consists of two portions, an inorganic portion (about 65% dry weight) and an organic portion (about 35% dry weight).
  • The inorganic portion of the matrix is mainly composed of calcium ph______(85%) and calcium car______(7%). They contribute to the str______ and rig_____of the bone. Small amounts of sodium and magnesium salts are also present.
  • The organic portion of the matrix is mainly composed of col_____ fibres and b___ cells, which has a high ten____ strength and makes the bone slightly flexible.

VI)Anatomy of the Skeleton of a Mammal

A mammalian skeleton can be divided into two major parts: the a____ skeleton, which consists of the s____, v______column, r___ and s______, and the a______skeleton, which consists of an anterior p______and posterior p_____ g_____, attached to each of which is a pair of l____.

A)The axial skeleton

a)The Vertebral column

  • It is the main a___ of the body. In adult, it consists of a linear series of ___ bones called vertebrae, placed end to end, separated by cartilaginous i______discs.
  • The v______are held together by l______which prevent their dislocation, but permit a certain degree of movement, so that the vertebral column as a whole isflex_____.
  • On the vertebrae are numerous projections for the att______of muscles. When the muscles are active, they may flex or b____ the vertebral column ventrally, dorsally or from side to side.
  • The vertebral column also gives protection to the s_____ c_____.

The structure of a typical vertebra:
  • Pairs of ‘articulating surfaces’ (zygapophysis) are present at both the anterior end and the posterior end of the vertebra. The anterior articulating surfaces of one vertebra fit against the posterior articulating surfaces of the vertebra in front of. This arrangement enables the vertebrae to articulate with each other.
  • the neural spine and transverse processes are for muscle attachment.
  • The centrum forms a central rigid body to the vertebra and withstand compression due to the bodyweight.
  • The neural arch encloses the spinal cord.
/

Reference Reading : ‘The Slip discs’

The I______discs between the fourth and fifth lumbar vertebrae are normally subject to the most severe com______forces in circumstances when the body is put under the greatest mechanical stress, perhaps due to the carrying of too heavy a load, or because of incorrect lifting and carrying post_____.

When a disc is 'slipped', its outer, fibrous coat becomes torn or weakened. The soft, elastic interior of the disc protrudes posteriorly, putting pr______upon the spinal c____ or spinal n______.

Since the nerve contains fibres from the leg, the sensation of pain often seems to come from the leg as well as the spine.

A summary of mammalian axial skeleton

Part of axial skeleton / Characteristics
Skull / Cranium / It encloses and protects the brain, the middle and inner ears
Jaw bones / It holds the teeth in sockets
The upper jaw bone fuses with cranium and is immovable.
The lower jaw bone articulates with cranium and is movable
Vertebral column / It forms the main axis of the body.
It consists of a series of vertebrae cushioned by intervertebral discs.
It is divided into five regions: cervical, thoracic, lumber, sacral and caudal region.
Rib cage / Ribs / Each rib has a bony vertebral part and a cartilaginous sternum part
True ribs attach directly to sternum
False ribs unite with the seventh true rib
Floating ribs have no anterior attachment.
Sternum / Provides attachment for the ribs at the front

B) The appendicular skeleton

a) Girdles

  • The pectoral and pelvic girdlesconnect the axial skeleton to the limbs.
  • Modified for m_____ attachment and art______with the limb bones.
  • The b___-and-s_____ joint enables the limbs to be moved through a number of planes and angles.

b) The Limbs

  • The limbs ofall mammals are designed on the same basic plan, that of the p______limb (five digits -fingers or toes).
  • There are numerous mod of the general plan, which are adaptations to the different m of life of different animals (ad radiation).
  • In some cases the number of digits per limb has been reduced during evolution.

C)Structure of a Long Bone

A long bone such as the femur, consists of two main regions: a central piece, called shaft (diaphysis) and two thickened heads (epiphyses singular: epiphysis) at the ends of the bone.

The heads articulate with other bones and are covered with a thin layer of c______. The remainder of the bone is covered with a tough, strong membrane called periosteum. P______contains a network of b_____ vessels and n______. Thus, o______and nu_____ can be carried to bonecells for their growth and development.
Beneath the periosteum is a layer of compactbone which is hard and dense. C______bone is thicker in the diaphysis than in the epiphysis. It enables the diaphysis to resistimpact exerted by solid objects. The diaphysis encloses the y______bonemarrow, a kind of fatty tissue.
The epiphysis consists of spongybone which is covered by a thin layer of compact bone. The spongy bone is made up of bonybars or tr______(trabecula = little beam)arranged in such a way that they are able to resist the forces (com______and ten______) applied upon the bone. In between the bars are many tiny cavities filled with red m______ which is a specialized tissue to produce b_____ cells. /
Spongy bone
/
Bone marrow cells

Reference reading: Osteoporosis (

Osteoporosis is a condition that causes bones to become moreporous (less solid and less dense), which gradually makes them weaker and more brittle.
Bones affected by osteoporosis:
  • Do not have enough solid calcium and phosphorus, and steadily lose their supportingproteinframework
  • Become thinner and more fragile than normal
  • Break more easily, particularly the spine, hip, and wrist

To maintain bone density, the body needs enough calcium and other minerals and must produce the proper amounts of several hormones, including estrogen in women and testosterone in men. In addition, an adequate supply of vitamin D is needed to absorb calcium from food and incorporate it into bones.
After age 30, bones slowly decreaseindensity. If the body cannot regulate the mineral content of bones, they become more fragile. The result is osteoporosis.
The human and economic costs of osteoporosis are significant. As many as 20 percent of the people who break their hip because of osteoporosis die within a year. Over age 70, the mortality within a year may increase to as much as 50 percent, and 30 percent may require help for the activities of daily living. Another 20 percent may be unable to walk for a year afterwards.

That's why preventing, detecting, and treating osteoporosis is so important.
Facts About Osteoporosis
  • Osteoporosis, called "the bone-thinning disease," is a common condition that affects over 25 million people each year.
  • 80 percent of people with osteoporosis are women.
  • 80 percent of women over age 65 have osteoporosis.
  • Osteoporosis is responsible for one and a half million fractures each year and costs $15 billion for fracture care. Fractures do heal with appropriate measures
  • After menopause, women lose about one to two percent of their bone density each year.
  • Although the vast majority of people with osteoporosis are women, 1.5 million men also have osteoporosis, and another 3.5 million men are at high risk.
  • By the age of 80, nearly half of all women show on an X-ray that they have had a fracture of their spine. Yet many cannot recall any injury or incident that would have caused the fracture.

What Causes Osteoporosis?
There is no single cause of osteoporosis.
Our bodies constantly build new bone and remove older bone. In childhood, more bone is built than removed, and so the bones grow in size. After age 30 or 40, however, the cells that build new bone do not keep up with those that remove bone. The total amount of bone then decreases, and osteoporosis may develop as a result.
The average rate of bone loss in men, and in women who have not yet reached menopause, is small. But after menopause, bone loss in women accelerates to an average of one to two percent a year.
This is because after menopause, the level of the female hormone estrogen in a woman's body sharply decreases. Estrogen protects the skeleton by helping the body's bone-forming cells to keep working. After menopause, when the level decreases, some of this protection is lost.
Activity stimulates new bone formation, but immobility (for example, after a bone fracture) can result in bone loss. This is called osteopenia, which means "bone deficiency."
People immobilized by bedrest and astronauts on weightless space flights have loss of bone density. Weight-bearing exercise is vitally important to help keep osteoporosis from developing.
Risk Factors
Certain risk factors greatly increase the chance of someone developing the condition. These risk factors are:
  • Menopause in women. The risk of developing osteoporosis is much higher in women after menopause. In fact, the earlier the menopause, the greater the risk. Most women, on average, begin menopause at age 45 to 55. After menopause, the ovaries produce less est_____, which results in less bone formation and more bone loss.
  • Hysterectomy that included removal of the ovaries. Younger women who have had both ovaries removed as part of their hysterectomy are also at higher risk. Younger women who have had a simple hysterectomy, with their ovaries left intact, are not at higher risk.
  • Age and gender. After we reach maturity, there is a gradual decrease in the total amount of bone formed, compared to the amount of bone removed. After age 30 or 40, this may lead to a gradual loss of bone, which occurs more rapidly in women than in men. At first, the loss is so gradual it cannot be detected. But people over age 40, and women in particular, are at increased risk.
  • Cigarettes. Smoking cigarettes may double the risk of developing osteoporosis. This is most likely because smoking lowers the estrogen level in the blood.
  • Family members with osteoporosis. The risk of developing osteoporosis seems to be higher if other blood relatives have the condition. This is particularly the case for women whose mothers have osteoporosis.
  • Women who are underweight. Women who are underweight for their height often develop osteoporosis more rapidly. Women who are overweight actually have less chance of developing osteoporosis. This may be caused by a difference in the production of estrogen in overweight women.
  • Lack of regular exercise. Regular exercise helps to delay osteoporosis and can even reverse its progression. On the other hand, lack of exercise can make people much more vulnerable to osteoporosis. Exercise, especially weight-bearing activity such as walking, stimulates the bone cells to be more active and to produce stronger bone. Without weight-b______activity, bones may become less dense and weaker.
  • Use of certain medications. Certain medications may increase the risk of developing osteoporosis. They seem to increase bone loss and decrease bone formation. The most common are cortisone-like drugs (used for asthma, lung disease, arthritis, and allergies). Thyroid medications may also contribute to osteoporosis if taken in high doses.
  • Medical problems. Certain medical conditions are likely to increase the risk of developing osteoporosis. These conditions include rheumatoid arthritis, chronic bronchitis and emphysema, hyperthyroidism (overactivity of the thyroid gland), malnutrition (especially when associated with heavy alcohol use), chronic liver disease, and some forms of intestinal disease.
  • Low calcium or vitamin D in your diet. If your diet is consistently low in calcium over the years, especially during the growth years, your risk of developing osteoporosis is increased. Calcium deficiency leads to less bone formation. Vitamin ___ is needed to help the body absorb calcium and maintain bone.
Why Teenagers Should Be Concerned
Teenage girls in particular need to be aware that osteoporosis in future years can be prevented.
During the teenage years, the bones are developing rapidly. Recent research has found that bone mass in women may peak as early as their early 20s. If teens get enough calcium, chances are good that their bones will have maximum development and strength.
But the foods that are the best sources of calcium - such as milk and cheese - also contain high calories. As a result, some calorie-conscious teens will eliminate these foods from their diet and may pay the price in later years. If calcium in their diet is consistently low, teens may need a calcium supplement to compensate.
In addition, high levels of phosphates, often found in soft drinks, can cause calcium loss from the bones. For this reason, experts recommend that teens limit their intake of soda.
Can Men Be Affected Too?
Yes. Twenty percent of the people who have osteoporosis are men. A leading medical researcher says that 1.5 million men have osteoporosis and another 3.5 million are at high risk. Experts believe that a decrease in the production of the male hormone testosterone, which happens as a natural part of aging, can accelerate osteoporosis.
How Can You Tell If You Are Developing Osteoporosis?
If your health care provider thinks that you may have or may be at risk for osteoporosis, you may need a bone mineral density (BMD) test (also referred to as a bone density test), which can detect osteoporosis and allow effective treatment to start.
Calcium intake
One of the most important ways to help prevent osteoporosis is to get enough calcium in your diet. Here is the recommended daily dietary allowance of calcium for various age groups:
  • Children, age 1-10- 800 mg daily
  • Teenagers, age 11-18- 1,200 mg daily
  • Pregnant teens - 1,600 mg daily
  • Pregnant women, age 19 and older - 1,200 mg daily
  • Breast-feeding women - 1,200 mg daily
  • Adults, male, up to age 65 - 1,000 mg daily
  • Adults, male, over age 65 - 1,500 mg daily
  • Adults, women, before menopause - 1,200 mg daily
  • Adults, women, after menopause - 1,500 mg daily
Here are some examples of calcium content in foods:
Food / Amount / Calcium
Pizza, cheese / 10" diameter / 620 mg
Milk, calcium fortified / 8 oz / 500 mg
Milk, skim, whole, 1%, or 2% / 8 oz / 300 mg
Yogurt, frozen, high-calcium / 8 oz / 500 mg
Yogurt, frozen (most flavors) / 6 oz / 150 mg
Sardines, canned with bones / 8 medium / 350-450 mg
Hormone Replacement Therapy
Menopause, as well as surgical removal of the ovaries, causes estrogen production to decrease. Low estrogen levels make women more vulnerable to osteoporosis. Women can protect themselves by taking estrogen to replace what their ovaries no longer produce naturally.
Hormone replacement therapy has been shown to entirely restore the rate of post-menopause bone loss to the pre-menopausal rate. It may even replace a small amount of bone already lost. It also controls hot flashes and other symptoms which can happen around the time of menopause.
For many years, hormone replacement therapy has been routinely given to women at menopause. Recent evidence shows that hormone replacement therapy may increase the risk of breast cancer or ovarian cancer.
Although hormone replacement therapy (HRT) has obvious and proven benefits, they must be weighed against possible long-term effects. It remains effective for prevention and treatment of osteoporosis and for relief of menopause symptoms. However, whether to begin hormone replacement therapy is a decision every woman must make for herself.

D)Joints