skeletal

Página 1

Distal means closer to the destination of the flow.

Groups of similar cells are organized into tissues. Organs are composed of groups of tissue that have common function & work together. Organ systems made up of organs with related functions & interact.

CELLS - All mammalian cells have the same basic structure: cell membrane, organelles, cytoplasm & nucleus. Molecules within the cell membrane can determine which substance can move in & out of the cell & can assist with the movement of some of these substances. Cell surface covered with various receptors (structures to which hormones & other chemicals outside of the cell attach to signal the cell to carry out particular functions.

ORGANELLES & CYTOPLASM - Inside the cell membranes are organelles (specialized organs within the cell that carry out specific functions) floating in the semiliquid substance called cytoplasm. Mitochondria power plants of cells, produces chemicals that provide the cell energy to carry out it's functions. The endoplasmic reticulum, ribosomes, & Golgi apparatus manufactures proteins, lipids & carbohydrates to be used by or shipped out of the cell. Lysosomes are sac-like organelles that take substances from the outside of the cell and break them down into raw material for use by other organelles.

NUCLEUS - Comparable to a brain for a cell; directs activity of other organelles. Surrounded by nuclear membrane that looks and functions much like a cell membrane. Nucleolus, organelle within the nucleus. Composed of ribonucleic acid (RNA) , which is involved in making proteins. Also inside the nucleus is the molecule deoxyribonucleic acid (DNA) "Blueprint for every cell as well as entire animal"

We consider DNA to be cell's blueprint & RNA to consist of cell's architects & construction workers. DNA messages are copied into the equivalent RNA molecule through a process called Transcription. RNA travels to cytoplasm, RNA message translated by endoplasmic reticulum & Golgi

Four phases of cellular mitosis: Prophase, Metaphase, Anaphase, Telophase.

PROPHASE: Chromosomes begin to condense & the nuclear membrane dissolves.

METAPHASE: The chromosomes line up in a row in the middle of the cell.

ANAPHASE: Chromosomes are pulled apart.

TELOPHASE: The cell begins to pinch in half, so that a new membrane eventually forms.

The body can be divided into approximately 11 organ systems:

Skeletal

Muscular

Digestive

Respiratory

Circulatory (And it's associated body fluids)

Integumentary (skin and all related components)

Urinary

Reproductive

Nervous

Sensory Organs

Endocrine

SELF-CHECK 1

Four types of passive transport: Disfussion,facilitated disfussion, osmosis, nervous

The study of the structure of body parts & how they relate to each other is called? anatomy

What is composed of two or more tissues that work together? organs

The four primary tissue types are? Connective, epithelial, muscle, nervous

Physiology is the study of the what of the body parts? functions

This organelle aids in intracellular digestion: mitochondria

Página 2

BONE FUNCTIONS//CHAPTER TWO

One important metabolic funcion of bones is the storage of minerals, also a site for production of blood cells (red blood cells, white blood cells & platelets produced in bone marrow)

Three types of cells present on bones: Osteoblasts, Osteocytes, & Osteoclasts.

Osteoblasts - Secreting material that forms bones.

Osteocytes - Primary cells of mature bones, but under right conditions can become Osteoblasts again (occurs when bone is damaged)

Osteoclast - Destructive cells, dissolving bone around them when needed.

Inner layer of periosteum contains osteoblasts, which allows bones to increase in size.

Skeletal bones can be divided into two major categories: Axial skeleton (body's central framework) & appendicular skeleton (supports axial skeleton)

Axial skeleton includes bones of: Skull, Spine, Ribs, & Sternum (central supporting structure of the body's organs)

Skull is organized into two areas: The cranial cavity (brain, facial bones, nose, jaw & eye sockets) Jaw is formed by two named bones. Maxilla, upper jaw & Mandible, lower jaw.

Spine consists of vertebraes (singular - Vertebra): Central support for the body in which limbs and organs are attached to. The spine can be divided into five areas -

The cervical or neck vertebrae

Thoracic or chest vertebrae

Lumbar or lower back vertebrae

Sacral or pelvic area vertebrae

Coccygeal or tail vertebrae

Ribs aka costae.

Bones of the thoracic limbs (starting closest to the spine & ending near the feet):

SCAPULA - (plural scapulae) aka shoulder blade. Attaches thoracic limb to body's dorsal surface, serves as pivot point for humerus (upper arm)

HUMERUS - better known as upper bone. connects scapula to the lower leg bones (radius and ulna).

RADIUS - in leg?

ULNA - in leg?

CARPAL BONES - collection of small bones

METACARPAL BONES - long bones lying side to side

PHALANGES - or toes

Dogs & Cats each have five metacarpal bones. The most distal bones on the thoracic limb are phalanges (phalanx, singular) called toes, or digits. Each digit is usually composed of two or three phalanges. The digits are numbered from one the most medial and corresponding to the human thumb, to five the most lateral (depending on the species of animal). Digits that don't bear weight are called "paradigits aka dewclaws" (Cats) some cats have extra dewclaws and may have a total of six or seven this condition is called, polydactyly.

The fundamental bones of the pelvic limbs, starting proximally & moving distally, include the:

Ilium

Ischium

Pubis

Femur

Patella

Tibia

Fibula

Tarsal bones

Metatarsal bones

Phalanges

The pelvis is comprised of three pairs of bones: Ilium, Ischium, & Pubis

ILIUM - Largest, roughly flat triangular bone, curves outward slightly at the cranial end (which is called the wing of the ilium) Caudal part of ilium is called the body or shaft. The spine attaches to the medial side of the ilium, called the sacral surface. Gluteal muscles of the pelvic limb attach to the lateral side, called the gluteal surface.

ISCHIUM - Cuadal & ventral to the ilium. Also flat somewhat horizontal (ilium vertical position). The caudal & lateral angle of the ischium is called, ischial tuberosity. At the junction between the ilium & the ischium is a concave joint surface called the, acetabulum. Also serves as a point of attachment for several muscles of the hip, pelvic limb & tail. Pubis lies medial & cranial completes the floor (ventral surface) of the pelvis. The left & right pubic bones form fuse at the median plate forming a seam called, pubic symphysis.

Patella or kneecap articulates. The medial epicondyle & lateral epicondyle attach the ligaments of the knee joint. The femur connects the pelvis to the Tibia & fibula & attaches the muscles that bends the knees and straighten the tarsal joint (equivalent of the ankle joint). The patella (kneecap) is a type of sesamoid bone, isn't directly connected to the femur, "floats" in trochlea of the femur. Some dogs - especially smaller breeds - have a shallow trochlea groove. which causes the patella to slip out of the trochlea groove in the medial direction. This condition is called patella luxation (requires surgery to correct the lameness and pain it creates). At the proximal end of the tibial crest is a projection of a bone called tibial tuberosity where ligaments connect the patella to the tibia.

The tarsal bones are a collection of bones that form the tarsal joint connecting the tibia and fibula at the proximal end. In domestic animals you'll find seven tarsal bones, depending on species, arranged in three rows. First row: Tarsal bones are calcaneus and talus. Calcaneus is the largest bone, almost same as the bone that forms your heel. Medial to the calcaneus is the talus, which forms most of the joint with the tibia and fibula. The talus has a pulley like shape a central groove with two circular ridges on each side.

Usually dogs & cats don't have dewclaws on hind feet.

Joints are the connection between two bones that help hold your bones together. Bones are attached at joints by a connective tissue called ligaments. Joints are also shock absorbers.

Four types of joints exist in the body:

Fibrous joints(synarthroses) - connects bones of the skull & teeth to the skull. Very little motion.

Synsarcoses joints - fleshy joints, between the thorax and scapula of certain animals.provides movement but no actual bone connection.

Synovial joints - Most common, found between most long muslces and provide flexibility. most complex structure of all joints.

Cartilaginous joints - Found between veterbraes in certain species, share both fibrous and synovial features.

The joint or articular surface of each bone is a layer of cartilage composed of chondrocyte (cartilage) and fibrous connective tissue called perichondrium. Between the articular cartilage of two bones lies the synovial fluid, sticky consistency like mucus and acts like a lubricant between the joint surface. The wall of is called synovial membrane, composed of fibrous tissue, blood vessels & cells called synoviocytes. Menisci add extra shock ability to joints under extra strain.

Joint names are based on the two bones being joined together.

Página 3

SELF-CHECK 2 Pg. 46

Osteoblast__I__ Cell that forms bone

Scapula__H__ Shoulder blade

Hip dysplasia__F__ Abnormal pelvic joint disorder with arthritis

Chondrocyte_J__ Cell that deposits cartilage & fibrous connective tissue

Tibia_A__ Lower-rear-leg bone

Stifle_D__ Knee joint

Dewclaws_C__ Digits that don't bear weight

Osteoclast__E__ Cell that breaks down

Perichondrium_G___ Tissue covering the epiphysis of each bone

Patella_B__ Kneecap

Two forms of bones: Compact & Cancellous

The four types of joints found in the body are: Fibrous (Synarthroses), Synsarcoses, Synovial (diarthroses), Cartilaginous (amphiarthroses)

The lower jaw bone is called the: Mandible

mammals have__seven____cervical vertebrae

The pelvis is made up of the following three bones: Ilium, Ischium, & Pubis

The knee joint is called the__Femorotibial__ or the ___Stifle___ joint.

Produces blood cells: Bone marrow

The two categories of skeletal bones are: Axial, Appendicular

The bones of the front limb include the: D Scapula, humerus, radius, & ulna

Which is not a segment of the spinal vertebrae: C Scapular

Página 4

CHAPTER 3 LAST CHAPTER

The muscular system

Three types of muscles exist in your body:

1. Skeletal (striated) muscle - Most "abundant" muscle tissue. Voluntary muscle tissue. Multinucleated (contains more than one nucleus.

2. Visceral (smooth) muscle - Found in internal organs. Hormones & involuntary nerve functions control it's contractions. Single nucleus. Also termed as "involuntary muscle"

3. Cardiac muscle - Only found in the heart. Somehow striated in appearance but isn't under voluntary control. Consistent rhythmic contractions. One or two nuclei per cell. Cell membrane is called sarcolemma; Cytoplasm is called sarcoplasm; Endoplasmic reticulum is called sarcoplasmic reticulum; Mitochondria is called sarcosomes.

Muscle Groups

Thoracic Limb: In the shoulder, supraspinatus muscle, cranial to spine of the scapula, extensor muscle of the joint. Other muscles that attach the humerus to the neck & spine aid the supraspinatus straighten the shoulder. Infraspinatus muscle, caudal to the scapular spine, flexes the shoulder joint in conjunction with muscles that attach the humerus to the spine or sternum. The pectoral muscles along with ventral chest to adduct the leg (pull it medially) by attaching the humerus to sternum. Other muscles such as the trapezius muscle, abduct the leg (pull it laterally) or pull it dorsally by attaching the scapular spine to the dorsal spine. Biceps brachii muscle lies on anterior surface of humerus and attaches the distal scapula to the radius, causing the shoulder to extent & or the elbow to flex. The caudal surface of the humerus is the triceps muscle. Gluteal muscles lie on the lateral surface of & act primarily to abduct the limb; however these muscles also extend the hip joint. Originate on the pelvic bones & end at the proximal femur. Biceps femoris muscle & semitendinosus muscle & the semsimembranosus muscle all lie on the caudal surface of the femur; collectively (altogether) called the hamstrings. Cranial surface of femur is the quadriceps femoris muscle that exposes the hamstrings.

Intercoastal muscles aid in breathing. As do the muscles that connect the ribs to spine, both of these sets are aided by the diaphragm. Skeletal muscles attach to the bone via connetive tissues called "tendons".

MUSCLE PHYSIOLOGY

Myofibers - Densely packed group of elongated cells (skeletal muscle consists of), these cells grouped into bundles called fascicles. Typical myofiber is 2-3 cm long & only 0.05 cm in diameter, made of small structures called myofibrils, contains thick & thin myofilaments made of protiens actin & myosin. Numerous capillaries keep the muscle supplied with oxygen & glucose that's needed to power the muscle contractions. Segment of myofibrils called - sarcomere (smallest unit of muscle). when muscles contract, the myosin filaments slide between the actin myofilaments (which shortens the myofibrils)When all the myofibrils contract simultaneously, the entire muscle group contracts.

Although smooth muscle contraction is similar to striated there are some differences. Actin & myosin filaments are active in smooth muscle.But they aren't organized as in striated muscle. Many smooth muscle cells are connected involuntary rather than voluntary nerves. The involuntary nerve endings secrete substances called "nuerotransmitters". They either stimulate or inhibit contraction, depending on type of receptor on the cell's surface , other smooth muscle cells are stimulated or inhibited by hormones rather than by nerve endings. another difference between smooth & striated is the ability of smooth muscle to maintain a steady state of contraction called "tone, without having to relax in between contractions. tone is often maintained by hormones that signal smooth muscle cells to remain in an indefinite state of concentration. smooth muscle can also contract by a greater fraction of it's length than striated muscle; thus, even though smooth muscle fibers are generally shorter than striated muscle, the smooth muscle cells can contract more relative to their size compared to striated muscle. The looser the arrangement of the actin & myosin filament in smooth muscle probably accounts for this. Cardiac muscle is unique ...cardiac muscle fibers branch, interwine & fuse with each other almost like a woven basket.Cardiac muscle is sometimes described as a syncytium (a multinuclear cell lie structure) closely bound together when one cell is excited all the others are excited as well.

Skeletal muscle functions

most skeletal muscles either exten (straighten) a joint or flex (bend) a joint, thus many muscles are described s extensor muscles or flexor muscles .

Página 5

SELF-CHECK 3 LAST CHAPTER

Myosin_E__Thick filament protein

Skeletal Muscle_D__Striated & multinucleated

Sarcomere_B__Contractile unit of the myofibril

Cardiac Muscle_F__Contain intercalated discs

Intercoastal Muscles_G__Muscles between ribs

Actin_I__Thin filament protein

Biceps Brachii_A__Muscle that flexes the elbow

Smooth Muscle_J__Contain dense protein

Sarcosomes_C__Mitochondria of muscle cells

Triceps__H_Muscle that extends the elbow

What are the three types of muscles? Striated (skeletal muscle), Smooth (visceral) muscle, Cardiac muscle

Cardiac muscle is sometimes described as a/an __syncytium_because all the muscle fibers contract at nearly the same time.

_Neurotransmitters__are the chemicals that submit the signal to contract between the nerve & muscle.

Tiny protein fibers that function to contract muscles are_Myofibrils___

Describe the type of nerve control, voluntary or involuntary for each muscle type: Striated muscle, voluntary control; Smooth muscle, involuntary muscle; Cardiac muscle, involuntary muscle.

The gastrocnemius muscle_flexes__the knee joint & the _extends__ankle joint

The steady state of contraction created by smooth muscle is called_tone___

The cell membrane of muscle cells is called the__sarcolemma__

A muscle that straightens a joint is called a/an_extensor__muscle

When the smooth muscle of a blood vessel constricts, this_decreases__the diameter of the blood vessel