Meiosis and Genetic Variation Quiz
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Questions and Answers

What is the primary result of meiosis in terms of chromosome number?

  • One diploid cell is maintained.
  • Four diploid daughter cells are produced.
  • Two diploid daughter cells are formed.
  • Four haploid daughter cells are produced. (correct)

What happens to the chromosomes during the anaphase of meiosis?

  • Chromosomes line up at the metaphase plate.
  • Homologous chromosomes are separated.
  • Chromosomes become indistinct chromatin.
  • Sister chromatids are pulled to opposite poles. (correct)

Which process contributes to genetic variation during meiosis?

  • Cleavage furrow formation during telophase.
  • Cytokinesis occurring after meiosis.
  • Independent assortment of chromosomes. (correct)
  • Replication of DNA before meiosis.

How does fertilization impact the chromosome number of the zygote?

<p>It creates a diploid zygote by merging two haploid gametes. (D)</p> Signup and view all the answers

What is the significance of the cleavage furrow during cytokinesis?

<p>It is responsible for dividing the cytoplasm and organelles. (A)</p> Signup and view all the answers

Which statement accurately describes the genetic characteristic of daughter cells produced by meiosis?

<p>They possess new combinations of genetic material. (C)</p> Signup and view all the answers

At which stage of meiosis do homologous chromosomes line up side by side?

<p>Prophase I (A)</p> Signup and view all the answers

What is the primary purpose of crossing-over during Prophase I?

<p>To exchange genetic material and increase genetic diversity. (A)</p> Signup and view all the answers

Meiosis II is most similar to which other type of cell division?

<p>Mitosis (A)</p> Signup and view all the answers

What phase follows after meiosis I without any DNA replication occurring?

<p>Interkinesis (B)</p> Signup and view all the answers

During which stage of meiosis do the centromeres divide?

<p>Meiosis II (D)</p> Signup and view all the answers

Which outcome results from the process of fertilization in meiosis?

<p>Restoration of the diploid number of chromosomes. (B)</p> Signup and view all the answers

What best describes the genetic composition of gametes produced through meiosis?

<p>They are haploid and genetically varied. (D)</p> Signup and view all the answers

What is the main purpose of genetic recombination during meiosis?

<p>To ensure offspring are genetically diverse. (C)</p> Signup and view all the answers

How many daughter cells are produced at the end of meiosis?

<p>Four (A)</p> Signup and view all the answers

In comparison to mitosis, meiosis results in daughter cells that are:

<p>Haploid and genetically diverse. (D)</p> Signup and view all the answers

What is the consequence of nondisjunction during meiosis?

<p>It produces abnormal chromosome conditions such as trisomy. (A)</p> Signup and view all the answers

Which event occurs during meiosis but not during mitosis?

<p>Crossing-over occurs. (B)</p> Signup and view all the answers

What indicates that meiosis has successfully occurred?

<p>Four genetically distinct haploid cells are formed. (D)</p> Signup and view all the answers

What characterizes the daughter cells produced by mitosis?

<p>They are genetically identical and diploid. (C)</p> Signup and view all the answers

How does independent alignment during meiosis contribute to genetic variation?

<p>By allowing for random assortment of maternal and paternal chromosomes. (D)</p> Signup and view all the answers

What is a significant effect of chromosomal translocation during meiosis?

<p>It may result in genetic disorders. (C)</p> Signup and view all the answers

What characterizes meiosis in terms of chromosome number?

<p>It reduces the chromosome number from 46 to 23. (C)</p> Signup and view all the answers

Where does spermatogenesis occur within the male reproductive system?

<p>In the seminiferous tubules. (C)</p> Signup and view all the answers

Which of the following is a function of the prostate gland?

<p>To secrete fluid that nourishes and protects sperm. (D)</p> Signup and view all the answers

Which process is responsible for introducing genetic variation during gamete formation?

<p>Meiosis. (C)</p> Signup and view all the answers

What is the primary energy source found in semen that aids sperm motility?

<p>Fructose. (B)</p> Signup and view all the answers

How many divisions are involved in the process of meiosis?

<p>Two divisions. (D)</p> Signup and view all the answers

Which reproductive organs contribute nutrients to seminal fluid?

<p>Seminal vesicles. (D)</p> Signup and view all the answers

What is the term for a fertilized egg formed by the fusion of sperm and egg?

<p>Zygote. (B)</p> Signup and view all the answers

Which of the following statements is true regarding egg production in females?

<p>Egg production occurs in the ovaries. (C)</p> Signup and view all the answers

What is the pH level of semen, and why is it significant?

<p>Slightly basic, to facilitate sperm mobility. (B)</p> Signup and view all the answers

What characterizes the cells formed at the end of meiosis I in spermatogenesis?

<p>They are haploid and consist of two chromatids. (A)</p> Signup and view all the answers

Which process occurs in oogenesis but not in spermatogenesis?

<p>Arresting at metaphase II. (A), Formation of polar bodies. (D)</p> Signup and view all the answers

How does meiosis contribute to genetic variation?

<p>Through independent alignment of chromosomes and crossing over. (C)</p> Signup and view all the answers

What defines the primary oocyte in female reproduction?

<p>It is arrested in prophase I and diploid. (C)</p> Signup and view all the answers

What is a direct consequence of spermatogenesis during puberty?

<p>Constant and high production of sperm. (A)</p> Signup and view all the answers

After meiosis II in oogenesis, what is the expected outcome?

<p>One egg and three polar bodies. (B)</p> Signup and view all the answers

What is the role of the polar body in oogenesis?

<p>To discard excess chromosomes. (D)</p> Signup and view all the answers

What triggers the completion of meiosis II in oocytes?

<p>Fertilization by a sperm. (D)</p> Signup and view all the answers

Which statement accurately describes metaphase I of meiosis?

<p>Homologous pairs align independently at the equator. (D)</p> Signup and view all the answers

Why is genetic recombination significant in meiosis?

<p>It introduces variability among offspring. (B)</p> Signup and view all the answers

The atlas vertebra allows the head to shake side to side, permitting the 'no' motion.

<p>False (B)</p> Signup and view all the answers

Intervertebral disks are composed of hyaline cartilage.

<p>False (B)</p> Signup and view all the answers

Ribs 8 to 12 are classified as true ribs.

<p>False (B)</p> Signup and view all the answers

The rib cage plays a part in protecting the liver and kidneys.

<p>False (B)</p> Signup and view all the answers

Floating ribs are defined as ribs 1 to 7 that do not connect to the sternum.

<p>False (B)</p> Signup and view all the answers

The primary function of the skeletal system is to create hormones.

<p>False (B)</p> Signup and view all the answers

The diaphysis of a long bone is the expanded end of the bone.

<p>False (B)</p> Signup and view all the answers

Red bone marrow is primarily found in the medullary cavity of long bones.

<p>False (B)</p> Signup and view all the answers

Canaliculi connect lacunae with one another and with the central canal in bone tissue.

<p>True (A)</p> Signup and view all the answers

Spongy bone is heavier than compact bone but lacks structural strength.

<p>False (B)</p> Signup and view all the answers

Compact bone is composed of tubular units called osteons.

<p>True (A)</p> Signup and view all the answers

Cartilage is stronger than bone and contains blood vessels for nutrient supply.

<p>False (B)</p> Signup and view all the answers

The periosteum is a connective tissue that covers only the ends of bones.

<p>False (B)</p> Signup and view all the answers

Fibrocartilage is found in the disks between vertebrae and in the knee joints.

<p>True (A)</p> Signup and view all the answers

Ligaments connect bone to muscle within the human body.

<p>False (B)</p> Signup and view all the answers

Estrogen exerts positive feedback on the anterior pituitary to increase FSH secretion during the follicular phase.

<p>False (B)</p> Signup and view all the answers

The luteal phase is characterized by high levels of estrogen and reduced levels of progesterone.

<p>False (B)</p> Signup and view all the answers

Menopause typically occurs between the ages of 30 and 40.

<p>False (B)</p> Signup and view all the answers

During the uterine cycle, low levels of estrogen and progesterone prompt the endometrium to disintegrate.

<p>True (A)</p> Signup and view all the answers

A surge of LH on day 14 of the cycle causes the regression of the corpus luteum.

<p>False (B)</p> Signup and view all the answers

Thick myofilaments are primarily made up of ______.

<p>myosin</p> Signup and view all the answers

The ______ is the plasma membrane of a muscle fiber.

<p>sarcolemma</p> Signup and view all the answers

Calcium is stored in the ______ reticulum of muscle cells.

<p>sarcoplasmic</p> Signup and view all the answers

The neurotransmitter released into the synaptic cleft is called ______.

<p>acetylcholine</p> Signup and view all the answers

Calcium ions bind to ______ during muscle contraction.

<p>troponin</p> Signup and view all the answers

The ______ is the space that separates the axon terminal and the sarcolemma.

<p>synaptic cleft</p> Signup and view all the answers

The vesicular follicle bursts, releasing the ______.

<p>oocyte</p> Signup and view all the answers

If the egg is not fertilized, the corpus luteum ______.

<p>disintegrates</p> Signup and view all the answers

The corpus luteum produces ______ and some estrogen.

<p>progesterone</p> Signup and view all the answers

Days 6 to 13 are known as the ______ phase, where estrogen increases and the endometrium thickens.

<p>proliferative</p> Signup and view all the answers

On day 14, the process of ______ occurs, signaling the release of the egg.

<p>ovulation</p> Signup and view all the answers

During the secretory phase from days 15 to 28, the corpus luteum secretes ______, which further prepares the endometrium.

<p>progesterone</p> Signup and view all the answers

If fertilization does not occur, the corpus luteum regresses, leading to a drop in ______ levels, which results in menstruation.

<p>progesterone</p> Signup and view all the answers

The fertilized egg, after several divisions, is referred to as a ______ when it reaches the embryonic stage.

<p>zygote</p> Signup and view all the answers

The process of bone formation is known as ______.

<p>ossification</p> Signup and view all the answers

During the growth of long bones, ______ are responsible for bone formation.

<p>osteoblasts</p> Signup and view all the answers

In endochondral ossification, the cartilage model is replaced by ______.

<p>bone</p> Signup and view all the answers

Vitamin D is essential for the absorption of ______ from food.

<p>calcium</p> Signup and view all the answers

The hormone that stimulates growth in bones is called ______.

<p>growth hormone</p> Signup and view all the answers

Osteocytes are mature bone cells that help regulate ______ in bone tissue.

<p>calcium</p> Signup and view all the answers

When the epiphyseal plates close, ______ can no longer occur.

<p>bone lengthening</p> Signup and view all the answers

Osteoblasts are responsible for forming ______ by secreting the organic matrix and promoting calcium deposition.

<p>bone</p> Signup and view all the answers

Intramembranous ossification primarily forms ______ bones, such as those in the skull.

<p>flat</p> Signup and view all the answers

Ossification refers to the process of ______ formation during the development of the skeletal system.

<p>bone</p> Signup and view all the answers

Osteocytes are mature bone cells that develop from ______, which have surrounded themselves with calcified matrix.

<p>osteoblasts</p> Signup and view all the answers

Endochondral ossification is the process by which ______ bones are formed from hyaline cartilage.

<p>long</p> Signup and view all the answers

Osteoblasts in the periosteum carry out further ______.

<p>ossification</p> Signup and view all the answers

Trabeculae form and fuse into ______ bone.

<p>compact</p> Signup and view all the answers

Endochondral ossification forms most ______, like the tibia.

<p>bones</p> Signup and view all the answers

The primary ossification center is where blood vessels bring ______ for bone formation.

<p>osteoblasts</p> Signup and view all the answers

The epiphyseal plate plays a vital role in ______ lengthening.

<p>limb</p> Signup and view all the answers

Cartilage cells are produced in the ______ zone of the epiphyseal plate.

<p>proliferating</p> Signup and view all the answers

The first step of endochondral ossification involves the formation of a ______ model.

<p>cartilage</p> Signup and view all the answers

As the primary ossification center develops, it leads to the formation of the ______ cavity.

<p>medullary</p> Signup and view all the answers

In the degenerating zone, cartilage cells are ______ off.

<p>dying</p> Signup and view all the answers

The layer nearest the epiphysis in the epiphyseal plate is called the ______ zone.

<p>resting</p> Signup and view all the answers

Smooth muscle fibers are striated and multinucleated.

<p>False (B)</p> Signup and view all the answers

Skeletal muscle contraction is involuntary and helps maintain a constant body temperature.

<p>False (B)</p> Signup and view all the answers

Cardiac muscle fibers are branched and interlock at intercalated disks.

<p>True (A)</p> Signup and view all the answers

All types of muscle tissue are striated and controlled voluntarily.

<p>False (B)</p> Signup and view all the answers

Cardiac muscle contraction can occur with nervous stimulation.

<p>False (B)</p> Signup and view all the answers

The fascia is the connective tissue that covers muscles and extends to become the tendon.

<p>True (A)</p> Signup and view all the answers

Bursae function primarily as fluid-filled sacs that provide rigidity to the joint area.

<p>False (B)</p> Signup and view all the answers

When the biceps brachii contracts, it serves as the antagonist muscle during the movement of the forearm.

<p>False (B)</p> Signup and view all the answers

The insertion of a muscle is the site where the muscle attaches to a stationary bone.

<p>False (B)</p> Signup and view all the answers

The primary role of skeletal muscles is to facilitate movement through the action of agonist and antagonist pairs.

<p>True (A)</p> Signup and view all the answers

The muscle that is contracting is known as the antagonist.

<p>False (B)</p> Signup and view all the answers

Skeletal muscles can work together to cause movement.

<p>True (A)</p> Signup and view all the answers

Myofibrils are the plasma membrane of a muscle fiber.

<p>False (B)</p> Signup and view all the answers

The myofibrils within a muscle fiber are composed of myofilaments.

<p>True (A)</p> Signup and view all the answers

Calcium is stored in the sarcolemma.

<p>False (B)</p> Signup and view all the answers

Glycogen in the sarcoplasm provides energy for muscle relaxation.

<p>False (B)</p> Signup and view all the answers

Thick myofilaments are primarily composed of actin.

<p>False (B)</p> Signup and view all the answers

Myoglobin in the sarcoplasm binds to carbon dioxide.

<p>False (B)</p> Signup and view all the answers

The sarcoplasmic reticulum is an essential site for protein synthesis in muscle fibers.

<p>False (B)</p> Signup and view all the answers

If both the agonist and antagonist muscles contract simultaneously, it results in movement.

<p>False (B)</p> Signup and view all the answers

Flashcards

Meiosis

A type of cell division that produces genetically different daughter cells.

Homologous Chromosomes

Matching pairs of chromosomes that carry genes for the same traits.

Synapsis

The pairing of homologous chromosomes during meiosis I.

Crossing-over

The exchange of genetic material between non-sister chromatids.

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Genetic Variation

Differences in genetic material among individuals in a population.

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Meiosis I

The first cell division in meiosis, creating two haploid cells.

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Prophase I

The first phase of meiosis I, where synapsis and crossing-over occur.

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Gametes

Reproductive cells (sperm and egg) produced by meiosis.

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Genetic Recombination

The process that creates genetically different offspring compared to their parents and siblings.

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Meiosis vs. Mitosis

Meiosis involves two divisions, producing 4 haploid cells, while Mitosis has one division, creating 2 diploid cells.

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Haploid Cells

Cells containing half the number of chromosomes as the parent cell.

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Diploid Cells

Cells containing the full set of chromosomes.

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DNA replication in Meiosis and Mitosis

DNA replicates once before both meiosis and mitosis.

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Daughter cells in Meiosis

Genetically different from each other and the original parent cell.

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Metaphase I

Homologous pairs align independently at the equator during meiosis I.

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Daughter cells in Mitosis

Genetically identical to each other and the parent cell.

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Spermatogenesis

The process of sperm production in males, involving meiosis.

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Nondisjunction

The failure of chromosomes to separate properly during meiosis.

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Monosomy

A genetic condition resulting in one less chromosome than normal.

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Oogenesis

The process of egg production in females, involving meiosis.

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Trisomy

A genetic condition resulting in one more chromosome than normal.

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Primary Spermatocyte

Diploid cell (2n) that undergoes meiosis I to produce secondary spermatocytes.

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Secondary Spermatocyte

Haploid cell (n) resulting from meiosis I of a primary spermatocyte.

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Spermatids

Haploid cells that mature into sperm.

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Primary Oocyte

Diploid cell (2n) in the ovary, arrested in prophase I of meiosis.

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Secondary Oocyte

Haploid cell (n) that leaves the ovary during ovulation.

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Polar Bodies

Small cells formed during oogenesis, holding discarded chromosomes; they disintegrate.

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Meiosis significance

Maintains chromosome number and results in genetic recombination.

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What is the purpose of meiosis?

Meiosis is a type of cell division that reduces the number of chromosomes in a cell by half, creating genetically unique gametes (sperm and egg) for sexual reproduction.

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Where does meiosis occur?

Meiosis takes place specifically in the testes of males (during sperm production) and the ovaries of females (during egg production).

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Haploid vs. Diploid

Haploid cells (n) have half the number of chromosomes as diploid cells (2n). Meiosis reduces a diploid cell to haploid gametes.

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Meiosis I vs. Meiosis II

Meiosis involves two successive divisions: Meiosis I separates homologous chromosome pairs, reducing the chromosome number. Meiosis II then separates sister chromatids, resulting in four haploid cells.

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Zygote

A zygote is formed when a sperm cell fertilizes an egg cell. It has 46 chromosomes (2n) since each gamete contributes 23.

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What is the function of the epididymis?

The epididymis is a coiled duct where sperm mature and are stored before being transported.

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What is the role of the prostate gland?

The prostate gland secretes a fluid that nourishes and protects sperm, contributing to the overall composition of semen.

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What is the function of seminal vesicles?

Seminal vesicles contribute nutrients, including fructose, to the seminal fluid to provide energy for sperm.

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What is the function of the urethra?

The urethra is a tube that conducts sperm from the reproductive system to the outside of the body.

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What are prostaglandins?

Prostaglandins are hormones found in semen that cause the uterus to contract, helping propel sperm toward the egg.

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What is Meiosis?

A specialized cell division that produces four daughter cells, each with half the number of chromosomes as the parent cell. This is also called reduction division.

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What's the unique characteristic of Meiosis?

It involves two consecutive cell divisions without an interphase in between.

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What is the result of Meiosis?

Four daughter cells, each with one of each type of chromosome, are produced. These cells are called haploid.

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What is the difference between a diploid cell and a haploid cell?

A diploid cell has two sets of chromosomes, while a haploid cell has only one set.

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How is the chromosome number of the daughter cells determined in Meiosis?

The parent cell is diploid (2n), which means it has two sets of chromosomes. Meiosis reduces the chromosome number to haploid (n), which means the daughter cells have only one set of chromosomes.

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Compact Bone

A dense, hard type of bone tissue that makes up the outer layer of most bones. It is organized into concentric rings called osteons, with a central canal containing blood vessels and nerves.

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Spongy Bone

A lighter, porous type of bone tissue found inside bones. It contains numerous thin plates called trabeculae, which provide strength and support while allowing for flexibility.

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Osteocytes

Bone cells that are responsible for maintaining the bone matrix and are located in lacunae within compact and spongy bone.

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Canaliculi

Tiny canals that connect lacunae, allowing for communication and nutrient exchange between osteocytes.

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Skeletal System Functions

The skeletal system provides support, movement, protection, blood cell production, mineral storage, and fat storage.

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Trabeculae

Thin plates of bone that form the structure of spongy bone, allowing for strength without excessive weight.

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Long Bone Structure

A long bone consists of a diaphysis (shaft), epiphyses (ends), medullary cavity (hollow space in diaphysis), and periosteum (outer covering).

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Types of Cartilage

Hyaline cartilage is smooth and found on joint surfaces. Elastic cartilage provides flexibility and is found in the ear. Fibrocartilage resists compression and is found in intervertebral discs.

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What does the medullary cavity contain?

The medullary cavity is located inside the diaphysis of a long bone and contains yellow bone marrow, which primarily stores fat.

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What is the function of the epiphyseal plate?

The epiphyseal plate, located between the epiphysis and diaphysis, is made of cartilage and allows for bone growth in length.

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What are spinal nerves?

Spinal nerves are bundles of nerve fibers that connect the spinal cord to the rest of the body. They control various functions, including muscle movement, sensation, and reflexes.

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What happens if the spinal cord or nerves are injured?

Injuries to the spinal cord or spinal nerves can lead to various problems, including paralysis or even death. This is because they are essential for transmitting signals to and from the brain.

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What are cervical vertebrae?

Cervical vertebrae are the bones in your neck. The first two, called atlas and axis, are especially important for head movement.

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What is the function of intervertebral disks?

Intervertebral disks are cushions located between vertebrae that act as shock absorbers and allow for flexibility. They can weaken over time, leading to pain.

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Rib cage function

The rib cage, made of vertebrae, ribs, and sternum, protects the heart and lungs and helps with breathing.

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Follicular Phase

The initial stage of the ovarian cycle where a follicle containing an egg matures.

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Ovulation

The release of a mature egg from the ovary, triggered by a surge of LH hormone.

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Corpus Luteum

A temporary gland that forms after ovulation, secreting progesterone and estrogen.

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Progesterone's Role in Uterine Cycle

Progesterone prepares the uterine lining for implantation if pregnancy occurs.

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Menopause Timeline

The cessation of the ovarian cycle, typically between ages 45 and 55.

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Agonist Muscle

The muscle that contracts and performs the primary movement.

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Antagonist Muscle

The muscle that opposes the agonist, relaxing or lengthening to allow the agonist's action.

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Sarcolemma

The plasma membrane of a muscle fiber.

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Sarcoplasm

The cytoplasm of a muscle fiber, containing glycogen and myoglobin.

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Myofibrils

Contractile parts of muscle fibers, running the length of the fiber, made of smaller myofilaments.

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Neuromuscular Junction

The point where a motor neuron's axon terminal meets a muscle fiber, allowing nerve signals to stimulate muscle contraction.

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Synaptic Cleft

The tiny gap between the axon terminal and muscle fiber at the neuromuscular junction, across which signals pass.

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Acetylcholine (ACh)

A neurotransmitter released by motor neurons at the neuromuscular junction, triggering muscle contraction.

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T Tubules

Inward extensions of the sarcolemma, which carry nerve signals deep into the muscle fiber, triggering calcium release.

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Proliferative Phase

The phase of the uterine cycle where the endometrium (lining of the uterus) thickens and becomes glandular due to increased estrogen production.

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Secretory Phase

The phase of the uterine cycle where the endometrium thickens further and produces a thick secretion due to increased progesterone production from the corpus luteum.

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What are the phases of the uterine cycle?

The uterine cycle has three phases: menstruation, proliferative, and secretory. Each phase is driven by different hormone levels and prepares the uterus for potential pregnancy.

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Ossification Zone

The fourth layer in bone growth where bone formation occurs, increasing the bone's length.

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Epiphyseal Plates

Growth plates made of cartilage located at the ends of long bones; they allow for bone lengthening until they close.

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Bone Remodeling

A continuous process where old bone is broken down by osteoclasts and new bone is built by osteoblasts, constantly renewing bone tissue.

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Calcium Homeostasis

The body's regulation of calcium levels in the blood, drawing calcium from bones if levels are low and depositing excess into bones when levels are high.

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Parathyroid Hormone (PTH)

A hormone produced by the parathyroid glands that stimulates osteoclasts, leading to bone breakdown and an increase in blood calcium levels.

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Vitamin D Deficiency in Children

Leads to rickets, a condition characterized by weak and deformed bones.

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Growth Hormone (GH)

A hormone that stimulates bone growth, requiring the presence of thyroid hormone for proper metabolism.

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What is endochondral ossification?

A process where cartilage models are replaced by bone, forming most bones, especially long bones like the tibia.

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What is the bone collar?

A layer of compact bone that forms around the diaphysis (shaft) of a bone during endochondral ossification.

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Primary ossification center

The first site of bone formation within the diaphysis, where blood vessels bring osteoblasts.

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Medullary cavity

The hollow space within the diaphysis, formed by the absorption of spongy bone by osteoclasts.

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Secondary ossification centers

Sites of bone formation that appear in the epiphyses (ends) of bones, starting shortly after birth.

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Resting zone

The layer of the epiphyseal plate closest to the epiphysis, where cartilage remains unchanged.

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Proliferating zone

The layer of the epiphyseal plate where chondrocytes produce new cartilage cells.

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Degenerating zone

The layer of the epiphyseal plate where cartilage cells are dying off, preparing for replacement by bone.

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Articular cartilage

Cartilage that covers the ends of long bones, providing smooth surfaces for joint movement.

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What are the three major types of joints?

The three major types of joints are fibrous, cartilaginous, and synovial. Fibrous joints are immovable, cartilaginous joints are slightly movable, and synovial joints are freely movable.

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Ball-and-socket joint

A type of synovial joint that allows movement in all planes, including rotation. Examples include the hip and shoulder joints.

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Hinge joint

A type of synovial joint that permits movement in only one direction. Examples include the elbow and knee joints.

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Osteoblasts

Bone-forming cells that secrete the organic matrix of bone and promote the deposition of calcium salts into the matrix.

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Fascicle

A bundle of skeletal muscle fibers, surrounded by connective tissue, forming a component of a larger muscle.

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Tendon

A strong, fibrous cord of connective tissue that attaches a muscle to a bone. It transmits the force of muscle contraction to the bone.

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Muscle Contraction & Heat

When a muscle contracts, ATP breaks down, releasing heat as a byproduct. This heat helps maintain body temperature.

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Myofilaments

Thread-like protein structures within myofibrils, responsible for muscle contraction.

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Thick Myofilaments

Made of myosin protein, responsible for pulling thin filaments during contraction.

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Thin Myofilaments

Made of actin protein, which is pulled by myosin during contraction.

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What are the 3 types of muscle tissue?

The three types of muscle tissue are smooth, cardiac, and skeletal. Each type has unique characteristics and functions.

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Smooth Muscle

Smooth muscle is found in the walls of hollow internal organs and blood vessels, controlling involuntary movements like digestion and blood flow.

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Cardiac Muscle

Cardiac muscle forms the heart wall, allowing rhythmic, involuntary contractions to pump blood.

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Skeletal Muscle

Skeletal muscle is attached to bones, enabling voluntary movements like walking and lifting.

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Study Notes

Skeletal System - Part 1

  • The skeletal system consists of two types of connective tissue: bone and cartilage.
  • Ligaments, formed of fibrous connective tissue, join the bones.
  • Functions of the skeleton:
    • Supports the body.
    • Works with the muscular system to move the body.
    • Protects internal organs (skull protects brain, rib cage protects heart and lungs, vertebrae protect spinal cord).
    • Produces blood cells.
    • Stores minerals (calcium and phosphate) and fat.

Anatomy of a Long Bone1

  • Diaphysis-shaft of the bone.
  • Medullary cavity-inside the diaphysis; its walls are made of compact bone.
  • The medullary cavity is lined with the endosteum and is filled with yellow bone marrow, which stores fat.
  • Epiphysis-expanded end of a long bone.
  • Composed of spongy bone that contains red bone marrow, where blood cells are made.

Anatomy of a Long Bone2

  • The epiphyses are coated with a thin layer of hyaline cartilage, also called articular cartilage, because it occurs at a joint.
  • Metaphysis-between the epiphysis and diaphysis.
    • Contains the epiphyseal plate, a region of cartilage that allows for bone growth.
  • Periosteum-connective tissue covering all bones; continuous with ligaments and tendons.

Bone 1

  • Two types of bone tissue: compact and spongy.
  • Compact bone is highly organized and composed of tubular units called osteons.
  • Osteocytes are bone cells; they lie in lacunae (singular, lacuna), tiny chambers arranged in concentric circles around a central canal.
  • Matrix fills the space between the rows of lacunae.

Bone 2

  • Tiny canals called canaliculi connect the lacunae with one another and with the central canal.
  • Osteocytes stay in contact with each other in the canaliculi.
  • They exchange nutrients and wastes through gap junctions that connect adjacent osteocytes.

Bone 3

  • Spongy bone contains numerous thin plates called trabeculae.
  • Although lighter than compact bone, spongy bone is still designed for strength.
  • Red bone marrow is in the spaces of spongy bone.
  • Produces all types of blood cells.
  • Osteocytes of spongy bone are irregularly placed within the trabeculae.

Cartilage1

  • Cartilage-not as strong as bone but is more flexible.
  • Matrix contains collagen and elastic fibers.
  • Chondrocytes-cartilage cells; lie within lacunae.
  • Has no nerves or blood vessels; relies on neighboring tissues for nutrient and waste exchange.
  • This makes it slow to heal.
  • Three types of cartilage: hyaline, fibrocartilage, and elastic cartilage.

Cartilage2

  • Locations of cartilage:
    • Hyaline cartilage: ends of long bones, nose, ends of ribs, larynx, and trachea.
    • Fibrocartilage: disks between vertebrae and in the knee.
    • Elastic cartilage: ear flaps.

Fibrous Connective Tissue

  • Made of rows of fibroblasts separated by bundles of collagenous fibers.
  • Makes up ligaments and tendons.
  • Ligaments connect bone to bone.
  • Tendons connect muscle to bone at a joint (also called an articulation).

Bones of the Axial Skeleton 2

  • The 206 bones of the skeleton are classified as the axial or appendicular skeleton.
  • Axial skeleton-midline of the body.
    • Mainly consists of the skull, vertebral column, and the rib cage.
  • Skull:
    • Formed by the cranium and facial bones.
    • Cranium contains and protects the brain.
    • In adults, made of eight bones.
    • In newborns, cranial bones are joined by membranous fontanels.
    • Usually close by the age of 16 months.

The Skull 2

  • Bones: frontal, parietal, occipital, temporal, sphenoid, ethmoid.
  • Foramen magnum-a hole in the occipital bone through which the spinal cord passes.
  • External auditory canal-in each temporal bone; leads to the middle ear.
  • The sphenoid completes the sides of the skull and contributes to forming the orbits (eye sockets).
  • The ethmoid bone also helps form the nasal septum.

The Vertebral Column1

  • Vertebral column-consists of 33 vertebrae.
  • There are four curvatures that provide more strength for an upright posture than a straight column.
  • Scoliosis-abnormal sideways curvature of the spine.
  • Kyphosis-abnormal posterior curvature; "hunchback."
  • Lordosis-abnormal anterior curvature; "swayback."

The Vertebral Column 2

  • Vertebral canal-in the center of the column; the spinal cord passes through.
  • Intervertebral foramina (singular, foramen, “a hole”) on each side of the column; spinal nerves travel through.
  • Spinal nerves control skeletal muscle contraction, among other things.
  • If the spinal cord and/or spinal nerves are injured, there can be paralysis or even death.

Types of Vertebrae

  • Cervical vertebrae-neck
    • Atlas-first cervical vertebra; holds up the head. Movement permits the “yes” motion of the head.
    • Axis-second cervical vertebra is named because it rotates around the long axis of the body when we shake the head "no."

Intervertebral Disks 1

  • Composed of fibrocartilage.
  • Prevent the vertebrae from grinding
  • Absorb shock caused by movements such as running, jumping, and even walking.
  • Allows the vertebrae to move as we bend forward, backward, and from side to side.
  • Become weakened with age and can rupture.
  • Pain results if a disk presses against the spinal cord and/or spinal nerves.

The Rib Cage (Thoracic Cage)

  • Composed of the thoracic vertebrae, the ribs and their associated cartilages, and the sternum.
  • Part of the axial skeleton.
  • Protects the heart and lungs.
  • Swings outward and upward upon inspiration and then downward and inward upon expiration.

The Ribs 1

  • There are 12 pairs; all connect directly to the thoracic vertebrae in the back.
  • Curve outward and then forward and downward.
  • True ribs-ribs 1 to 7; connect directly to the sternum by means of a long strip of hyaline cartilage called costal cartilage.
  • False ribs-ribs 8 to 12; their costal cartilage does not connect directly to the sternum.
  • Floating ribs-ribs 11 and 12; they have no connection with the sternum.
  • Sternum (breastbone)
    • Along with the ribs, it helps protect the heart and lungs.

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Related Documents

Muscular System Part 1 PDF
Biology Skeletal System PDF
Skeletal System- Part II (PDF) - Abu Dhabi University Fall 2023

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