ANAPHY

Anatomy and Physiology Reviewer

Week 2

Human Organism

KEY TERMS:

·        Developmental anatomy studies the structural changes that occur between conception and adulthood.

·        Embryology (em-bree-OL-oh-jee), a  subspecialty  of  developmental  anatomy,  considers  changes  from  conception  to  the end of the eighth week of development.

·        Cytology  (sigh-TOL-oh-jee;  cyto, cell) examines the structural features of cells.

·        Histology, (his-TOL-oh-jee; hist, tissue) examines tissues, which are composed of cells and the materials surrounding them.

·        Gross   anatomy,   the   study   of   structures   that   can   be   examined without the aid of a microscope, can be approached either  systemically  or  regionally.

·        System, a  group  of  structures  that  have  one  or  more  common  functions,  such  as  the    cardiovascular,  nervous,  respiratory,  skeletal,  or  muscular  systems. 

·        Anatomical anomalies, are physical characteristics that differ from the normal  pattern.  Anatomical  anomalies  can  vary  in  severity  from  relatively  harmless  to  life-threatening.  For  example,  each  kidney  is normally supplied by one blood vessel, but in some individuals a kidney is supplied by two blood vessels. Either way, the kidney receives  adequate  blood.  On  the  other  hand,  in  the  condition  called  “blue  baby”  syndrome,  certain  blood  vessels  arising  from  an infant’s heart are not attached in their correct locations; blood is  not  effectively  pumped  to  the  lungs,  and  so  the  tissues  do  not  receive adequate oxygen.

They are the unusual or abnormal body structures that differ from the typical human anatomy. These differences can be present from birth and may or may not cause health problems.

Example: Some people are born with an extra finger, which is an anatomical anomaly.

·        Cell physiology, examines the processes occurring in cells such as energy production from food or the study of how cells work. It looks at how cells carry out their basic functions, like producing energy, moving materials in and out, and responding to signals.

Example: Cell physiology explains how muscle cells use energy to contract and make your body move.

·        Exercise physiology  focuses  on  the  changes  in  function  and  structure  caused  by  exercise.

ANATOMY

·        Word Greek, ana, up + tome, a cutting. To dissect, cut apart and separate.

·        Scientific discipline that investigates the body’s structure.

·        Examines the relationship bet. The structure of a body part and its function.

·        Ranges of studies; Microscopic organization, and the process by which it developed. Structure of body parts.

TWO BASIC APPROACHES TO THE STUDY OF ANATOMY

·        Systemic anatomy, study of the body by systems or group of structures that work together to perform a unique body function.

Example/s: Circulatory, Nervous, Integumentary and Muscular systems etc..

TYPES OF SYSTEMIC PHYSIOLOGY:

-        Cardiovascular physiology, focuses on the heart and blood vessels.

-        Neurophysiology, focuses  on  the  function  of  the  nervous  system. 

·        Regional anatomy, study of the organization of the by areas or study of the body by specific regions of the body.

Example: Head, abdomen, or arm etc..

EXAMINATION OF THE INTERNAL STRUCTURES OF A LIVING PERSON

·        Surface anatomy, AKA “Topographic” the study of external features, since there are some deep structures that are obvious. Meaning, we can palpate them through skin. We can study and examine them through the surface anatomy.

Example: Bony projection. A part of a boone that sticks out from the main body of the bone, a bump or ridge you can feel under the skin.

·        Anatomical imaging, is a way to see inside the body using techniques like X-rays, MRIs, or CT scans. These images help doctors find problems or understand what’s going on inside without surgery.

Example: An X-ray is often used to see if a bone is broken.

PHYSIOLOGY

·        Which means, “the study of nature”

·        A process of the scientific discipline that deals with the process of functions of living things.

·        Examining the body’s responses to stimuli.

·        Examine the body’s maintenance to stable internal conditions within a narrow range of values in a constantly changing environment.

·        Physiology  often  examines  systems  rather  than  regions  because  a  particular  function  can  involve  portions  of a system in more than one region.

MAJOR GOALS OF PHYSIOLOGY:

(1)   examining  the  body’s  responses  to  stimuli and (2) examining the body’s maintenance of stable internal  conditions  within  a  narrow  range  of  values  in  a  constantly  changing environment or understanding how the body maintains conditions within a narrow range of values in the presence of continually changing environment.

STRUCTURAL & FUNCTIONAL ORGANIZATION OF THE HUMAN BODY

·        The  body  can  be  studied  at  six  levels  of  organization:  chemical,  cell, tissue, organ, organ system, and whole organism.

·        Chemical level: The body is made up of atoms like hydrogen and carbon. These atoms combine to form molecules, which then have specific jobs based on their structure. For example, collagen is a strong, rope-like protein that gives skin its strength and flexibility. As we age, collagen changes, making the skin more fragile.

·        Cell level: Cells are the building blocks of all living things. Molecules come together to make cells. Inside each cell are structures called organelles that do specific tasks, like digestion or energy production. For example, the nucleus holds the cell’s genetic information, and mitochondria produce energy in the form of ATP.

·          Tissue level: Cells group together to form tissues, which perform specific functions. There are four main tissue types:

Epithelial (covers and protects)

Connective (supports and binds)

Muscle (moves)

Nervous (sends signals)

·         Organ level: Tissues combine to form organs, which perform specific functions. Examples of organs include the heart, stomach, and lungs.

·        Organ system level: Organs work together to form organ systems that carry out tasks needed to keep the body running. There are 11 major organ systems, such as:

Cardiovascular (heart and blood vessels)

Digestive (stomach, intestines)

Respiratory (lungs)

Urinary (kidneys, bladder)

·        The simplest level of organization in the human body is the atom. Atoms combine to form molecules. Molecules aggregate into cells. Cells form tissues, which combine with other tissues to form organs. Organs work in groups called organ systems. All organ systems work together to form an organism.

CHARACTERISTICS OF LIFE:

1.      Organization: All living things are made up of smaller parts working together in an organized way. For example, cells make up tissues, tissues form organs, and organs create organ systems, which work together to keep the body functioning.

Life is organized into different levels starting with: Cells, tissues, organs, organ systems, organism.

2.      Metabolism: This refers to all the chemical reactions happening inside the body to keep it alive. It includes breaking down food for energy (like digesting food) and using that energy to build or repair body parts.

3.      Responsiveness: Living things can respond to changes in their environment. Organism’s ability to sense changes in its internal or external environment and adjust those changes. For example, when you touch something hot, you quickly pull your hand away. This is the body’s way of reacting to protect itself.

4.      Growth: Growth means increasing in size, either by making more cells or increasing the size of existing cells. It’s how living things get bigger or repair themselves.

5.      Development: Development involves changes that occur over time, such as cells becoming specialized for specific tasks or the body maturing as you grow from a baby to an adult. Beginning with fertilization and ending at death.

Differentiation: involves changes in a cell’s structure and function from an immature, generalized state to a mature, specialized state or it is when cells change from a general type to a more specialized one. For example, during development, some cells become muscle cells, while others become nerve cells, each with specific functions.

Morphogenesis: change in shape of tissues, organs and the entire organism or it is the process where the body takes its shape and form. It's how cells, tissues, and organs are arranged and structured during growth and development.

6.      Reproduction: This is the process by which living things create new individuals, ensuring the survival of the species. Reproduction can happen sexually (with two parents) or asexually (with one parent).

HOMEOSTASIS

·        Homeo, the same + stasis, standing

·        It is the body's way of keeping everything balanced and stable, like maintaining a steady temperature or proper blood sugar levels, even when the environment changes.

Changes in internal body conditions are called variables because their  values  are  not  constant.  To  achieve  and  maintain  homeo-stasis,  the  body  must  actively  regulate  responses  to  changes  in  variables. Variables include such conditions as body temperature, volume, chemical content and pH of body fluids, as well as many other  variables.  For  our  cells  to  function  normally,  all  variables  must be maintained within a narrow range.

This narrow range is referred to as a normal range. Homeo-static  mechanisms  normally  maintain  body  conditions  near  an  ideal  normal  value  or  setpoint. Note  that  these  mechanisms  are  not  able  to  maintain  body  conditions  preciselyat  the  set  point.  Rather,  body  conditions  increase  and  decrease  slightly around the set point. Keep in mind that these fluctuations are  minimal.  For  example,  normal  body  temperature  does  not  typically vary more than 1°F above or below normal.

Homeostasis is regulated by feedback loops:

FEEDBACK LOOPS:

1.      Receptor: This detects any changes in the body, like a sensor. For example, if the body gets too hot, the receptors in the skin notice the temperature change.

2.      Control Center: This is like the brain of the system. It processes the information from the receptor and decides what to do. In many cases, the brain acts as the control center.

3.      Effector: This carries out the response. If the body is too hot, the effector (like sweat glands) helps cool you down by making you sweat.

TWO TYPES OF FEEDBACK LOOPS:

-        Negative Feedback: This is the most common. It works to bring the body back to normal when something is off. For example, if your blood pressure is too high, negative feedback will work to lower it.

-        Positive Feedback: This is less common and strengthens the change instead of reversing it. For example, during childbirth, positive feedback causes stronger and more frequent contractions until the baby is born.

Feedback loops maintain homeostasis. Receptors signal the control center that a variable has deviated outside its normal range. The control center regulates the action of the effectors, which produce a response that returns the variable to the set point. In negative feedback, the return to set point stops the response.

TERMINOLOGY AND THE BODY PLAN

BODY POSITIONS:

·        Anatomical Position, refers  to  a  person  standing  erect  with  the  face directed forward, the upper limbs hanging to the sides, and the  palms  of  the  hands  facing  forward. A  person  is supine  when  lying  face  upward  and  prone  when  lying  face  downward. In  anatomical  position,  the  head  is  above  the  feet,  but  if  a  person were to do a handstand, the head would be closer to the ground than the feet. However, we would still refer to the posi-tion  of  the  head  as  being  above  the  feet  because  the  point  of  reference for anatomical structures is the body, not the position of the body structure compared to the earth.

DIRECTIONAL TERMS:

·        Describe  parts  of  the  body  relative  to  each  other. Important directional terms are illustrated in figure 1.9 and summarized  in  table  1.2.  It  is  important  to  become  familiar  with  these  directional  terms  as  soon  as  possible  because  you  will  see  them repeatedly throughout this textbook. Right and left are used as  directional  terms  in  anatomical  terminology.  Superior means above,  and inferior means  below; anterior  is  used  for  “in  front  of,” and posterior is used for “behind.”

For  human  anatomy,  the  term  superior  is  used  interchange-ably  with  the  term  cephalic  (SE-FAL-ik;  head),  and  the  term  inferior  is  used  interchangeably  with  caudal  (KAW-dal;  tail). In addition, anterior is synonymous with ventral (belly) and posterior is syn-onymous with dorsal (back).

Proximal  means  “close  to,”  whereas  distal  means  “far  from.”  These  terms  are  used  to  refer  to  relative  positions  of  structures,  such  as  on  the  limbs.  Each  limb  is  attached  at  its  proximal  end  to  the  body,  and  the  distal  end,  such  as  the  hand,  is  farther  away.  Proximal  and  distal  can  also  describe  a  structure’s  position  relative  to  another,  such  as  the  kidney  structures  the  proximal  and  distal  convoluted  tubules.  Their  position  is  described  relative  to  another  kidney  structure  used  for filtration.

Medial  means  “toward  the  midline,”  and  lateral  means  “away from the midline.” The nose is in a medial position in the face, and the eyes are lateral to the nose. Superficial describes a structure close to the surface of the body, and deep is toward the interior of the body. The skin is superficial to muscle and bone.

BODY PARTS AND REGIONS:

Abdominal Quadrants

·        The right-upper

·        The left-upper

·        The right-lower

·        The left-lower

Regions

·        Epigastric

·        Right and left hypochondriac

·        Umbilical

·        Right and left lumbar

·        Hypogastric

·        Right and left iliac

The  central  region  of  the  body  consists  of  the  head,neck,and trunk.  The  trunk  can  be  further  divided  into  three  regions:  (1) the thorax, (2) the abdomen, and (3) the pelvis. The thorax is the chest cavity where the heart and lungs are located. The abdo-men  contains  organs  such  as  (1)  the  liver,  (2)  the  stomach,  and  (3) the intestines. The pelvis contains the bladder and reproductive organs. The upper limb is divided into (1) the arm, (2) the forearm, (3) the wrist, and (4) the hand. The arm extends from the shoul-der to the elbow, and the forearm extends from the elbow to the wrist.  The  lower  limb  is  divided  into  (1)  the  thigh,  (2)  the  leg,  (3) the ankle, and (4) the foot. The thigh extends from the hip to the knee, and the leg extends from the knee to the ankle. Note that, contrary  to  popular  usage,  the  terms  arm  and  leg  refer  to  only  a  part of the limb.

The   abdomen   is   often   subdivided   superficially   into   quadrants  by  two  imaginary  lines—one  horizontal  and  one  vertical—that  intersect  at  the  navel  (figure  1.11a).  The  quad-rants  formed  are  (1)  the  right-upper,  (2)  the  left-upper,  (3)  the  right-lower, and (4) the left-lower quadrants. In addition to these quadrants, the abdomen is sometimes subdivided into regions by four imaginary lines: two horizontal and two vertical. These four lines create a “virtual” tic-tac-toe grid on the abdomen, resulting in nine regions: (1) epigastric, (2) right and left hypochondriac,  (3)  umbilical,  (4)  right  and  left  lumbar,  (5)  hypogastric,  and  (6)  right  and  left  iliac  (figure  1.11b).  Health  professionals  use  the quadrants and regions as reference points for locating under-lying  organs.  For  example,  the  appendix  is  in  the  right-lower  quadrant,  and  the  pain  of  an  acute  appendicitis  is  usually  felt  there.

PLANES:

Is useful to describe the body as having imaginary flat surfaces.

·        Sagittal Plane, separates the body or a structure into right and left halves.

·        Median Plane, a sagittal plane that passes through the midline of the body, dividing it into equal right and left halves.

·        Transverse (horizontal) plane, runs parallel to the ground, dividing the body into superior and inferior portions.

·        Frontal (coronal) plane, divides the body into front (anterior) and back (posterior) halves.

·        At times, it is useful to describe the body as having imaginary flat surfaces, called planes, passing through it (figure 1.12). A plane divides, or sections, the body, making it possible to “look inside” and observe the body’s structures.

1.   A sagittal  (SAJ-ih-tal)  plane  separates  the  body  or  a  struc-ture into right and left halves. The word sagittal means “the flight of an arrow” and refers to the way the body would be split by an arrow passing anteriorly to posteriorly.

 2. A median  plane  is  a  sagittal  plane  that  passes  through  the  midline  of  the  body,  dividing  it  into  equal  right  and  left  halves.

3. A transverse (horizontal) plane runs parallel to the ground, dividing the body into superior and inferior portions. 4. A frontal  (coronal)  (KOHR-oh-nal,  koh-ROH-nal;  crown)  plane divides the body into front (anterior) and back (poste-rior)  halves.  For  example,  the  coronal  suture  on  the  skull  is  located across the top, where a person might wear a crown.

Organs  are  often  sectioned  to  reveal  their  internal  structure  (figure   1.13).   A   cut   through   the   length   of   the   organ   is   a   longitudinal section, and a cut at a right angle to the length of an organ is a transverse (cross)section. If a cut is made across the the  length  of  an  organ  at  other  than  a  right  angle,  it  is  called  an  oblique section.

CELL BIOLOGY:

Structures of a cell

1. Structures of a Cell

• Plasma/Cell Membrane: The outer layer that protects the cell and controls what goes in and out.

• Nucleus: The cell's control center, holding DNA that regulates cell activities.

• Cytoplasm: A jelly-like fluid inside the cell where all organelles are found.

• Organelles: Tiny structures inside the cell that perform specific functions:

  • Endoplasmic Reticulum (ER):

    • Rough ER: Has ribosomes and helps make proteins.

    • Smooth ER: No ribosomes, helps make fats and detoxifies substances.

  • Ribosomes: Make proteins for the cell.

  • Golgi Apparatus: Packages and ships proteins and lipids.

  • Lysosomes: Break down waste and old cell parts.

  • Peroxisomes: Break down fatty acids and toxins.

  • Proteasomes: Break down damaged proteins.

  • Mitochondria: Produce energy (ATP) for the cell.

  • Centrosomes/Centrioles: Help in cell division.

  • Cilia: Small hair-like structures that help move substances across the cell’s surface.

  • Flagella: Tail-like structures that help the cell move (like in sperm cells).

  • Microvilli: Increase surface area to help absorb nutrients.

2. Plasma Membrane Components

• Membrane Lipids:

  • Phospholipids: Form the main structure of the cell membrane.

  • Cholesterol: Adds stability to the membrane.

• Membrane Proteins:

  • Marker Molecules: Help cells recognize each other.

  • Attachment Proteins: Help cells stick to other cells or surfaces.

  • Transport Proteins:

    • Channel Proteins: Allow substances to pass through the membrane.

    • Carrier Proteins (Transporters): Carry substances across the membrane.

    • ATP-Powered Pumps: Use energy to move substances against their concentration gradient.

  • Receptor Proteins: Receive signals from outside the cell.

  • Enzymes: Speed up chemical reactions on the membrane.

3. Membrane Transport Mechanisms

Passive Transport (No energy needed):

• Diffusion: Movement of molecules from high to low concentration.

• Osmosis: Movement of water from high to low water concentration.

• Facilitated Diffusion: Transport proteins help move substances from high to low concentration.

Vesicular Transport:

• Endocytosis: Cell takes in large particles.

  • Phagocytosis: Cell "eats" solid particles.

  • Pinocytosis: Cell "drinks" liquid particles.

• Exocytosis: Cell releases substances to the outside.

Active Transport (Requires energy):

• Active Transport: ATP is used to move substances from low to high concentration.

• Secondary Active Transport: Uses the energy from one substance moving down its concentration gradient to move another substance up its gradient.

4. Cell Life Cycle

The cell life cycle includes all the changes a cell goes through from formation to division.

• Interphase: The phase where the cell grows, performs its normal functions, and prepares to divide by copying its DNA.

• Cell Division:

  • Mitosis: The process of dividing the nucleus into two identical nuclei.

  • Cytokinesis: The division of the rest of the cell (cytoplasm) into two new cells.

• Apoptosis: Programmed cell death; the cell self-destructs when it’s damaged or no longer needed.

Phases of Mitosis:

1. Interphase: DNA is copied.

2. Prophase: Chromosomes condense, and the nuclear membrane disappears.

3. Metaphase: Chromosomes line up in the middle of the cell.

4. Anaphase: Chromosomes are pulled apart to opposite sides of the cell.

5. Telophase: Two new nuclei form, completing nuclear division.

WEEK 3

TISSUES

·        Groups of specialized cells and the extracellular substances surrounding them.

HISTOLOGY

·        The microscopic study of tissue

4 PRIMARY TISSUES: Start of individual’s structures

·        Epithelial tissue

·        Connective Tissue

·        Muscle Tissue

·        Nervous Tissue

EMBRYONIC TISSUES

·        the early layers of cells in an embryo that eventually develop into all the organs and tissues of the body. They form during the early stages of development and are classified into three primary layers called germ layers

1. Ectoderm: The outer layer that forms structures like the skin, hair, nails, and the nervous system (brain, spinal cord). A portion of the ectoderm called neuroectoderm becomes the nervous system.

2. Mesoderm: The middle layer that forms muscles, bones, blood vessels, the heart, and connective tissues.

3. Endoderm: The inner layer that develops into the lining of the digestive tract, liver, lungs, and other internal organs.

These three layers work together to build all the tissues and organs of the body as the embryo grows.

EPITHELIAL TISSUES/EPITHELIUM

·        Covers and protects surfaces, both outside and inside the body.

FUNCTIONS:

Epithelial tissue serves several important functions in the body:

1. Protection: It covers and protects underlying tissues (e.g., skin).

2. Absorption: It absorbs substances, such as nutrients in the intestines.

3. Secretion: It produces and releases substances like mucus, hormones, and enzymes (e.g., glands).

4. Excretion: It helps remove waste products (e.g., sweat glands).

5. Filtration: It filters substances, especially in the kidneys.

6. Sensation: Some epithelial tissues have nerve endings for sensory detection (e.g., skin and taste buds).

Types of Epithelium:

Epithelial tissue is classified based on the number of layers and the shape of cells.

Based on Layers:

1. Simple Epithelium: One layer of cells.

   • Function: Allows for easy diffusion, absorption, and filtration.

   • Example: Lining of blood vessels, alveoli in lungs.

2. Stratified Epithelium: Multiple layers of cells.

   • Function: Protects against friction and abrasion. Secretion. Absorption.

   • Example: Skin, lining of the mouth.

3. Pseudostratified Epithelium: Appears to have multiple layers, but all cells touch the basement membrane. Often ciliated with goblet cells secreting mucus.

   • Function: Secretion and movement of mucus.

   • Location: Lining of nasal cavity, nasal sinuses, and auditory tubes. Pharynx, trachea, and bronchi of the lungs.

   • Example: Respiratory tract.

Based on Cell Shape:

1. Squamous: Flat, thin cells.

   • Function: Allows for rapid diffusion or filtration.

   • Example: Lining of lungs, capillaries.

2. Cuboidal: Cube-shaped cells.

   • Function: Secretion and absorption.

   • Example: Glands, kidney tubules.

3. Columnar: Tall, column-like cells.

   • Function: Absorption and secretion.

   • Example: Lining of the stomach, intestines.

4. Transitional Epithelium: Cells that change shape between flat and cuboidal, depending on the organ's stretch.

   • Function: Allows organs to expand and contract.

   • Example: Bladder.

These different types of epithelial tissues perform specialized functions based on where they are located in the body.

Glands

Definition: Glands are specialized organs that produce and release substances, such as hormones, enzymes, and sweat.

2 Types of Glands:

1. Exocrine Glands:

   • Definition: Glands that release their products through ducts onto surfaces (like skin or into body cavities).

   • Types:

     • Merocrine Glands: Secrete products by exocytosis (e.g., sweat glands).

     • Apocrine Glands: A part of the cell breaks off with the product (e.g., mammary glands).

     • Holocrine Glands: Entire cells break down to release the product (e.g., sebaceous glands in the skin).

2. Endocrine Glands:

   • Definition: Glands that release hormones directly into the bloodstream.

   • Example: Thyroid gland secreting hormones that regulate metabolism.

Connective Tissues and Functions

Definition: Connective tissue supports, binds, and protects other tissues and organs.

Types:

1. Dense Connective Tissue:

   • Function: Provides strong connections.

   • Example: Tendons (connect muscle to bone).

2. Adipose Tissue (Fat):

   • Structure: Large fat-filled cells.

   • Function: Stores energy, insulates, and cushions.

   • Location: Under the skin, around organs.

3. Areolar Tissue:

   • Structure: Loose network of fibers.

   • Function: Cushions organs, holds tissue fluids.

   • Location: Beneath the skin, around blood vessels.

4. Compact Bone:

   • Structure: Dense, solid bone.

   • Function: Provides strength and support.

   • Location: Outer layer of bones.

5. Blood:

   • Structure: Liquid matrix with red and white blood cells.

   • Function: Transports nutrients, gases, and wastes.

   • Location: Within blood vessels.

Classification: Embryonic Connective Tissue

1. Mesenchyme:

   • Structure: Star-shaped cells in a gel-like matrix.

   • Function: Gives rise to all connective tissues.

   • Location: Embryos.

2. Mucous Connective Tissue:

   • Structure: Jelly-like.

   • Location: Umbilical cord.

Classification: Adult Connective Tissue

Loose Connective Tissue:

1. Areolar Connective Tissue:

   • Structure: Loose arrangement of fibers.

   • Function: Binds skin to muscles, provides nutrients to epithelium.

   • Location: Under the skin, around organs.

2. Adipose Tissue:

   • Structure: Fat-filled cells.

   • Function: Stores fat, insulates.

   • Location: Around organs, under the skin.

3. Reticular Tissue:

   • Structure: Network of reticular fibers.

   • Function: Supports soft organs.

   • Location: Spleen, lymph nodes.

Dense Connective Tissue:

1. Dense Regular Collagenous Connective Tissue:

   • Structure: Parallel collagen fibers.

   • Function: Provides strength in one direction.

   • Location: Tendons, ligaments.

2. Dense Regular Elastic Connective Tissue:

   • Structure: Elastic fibers.

   • Function: Allows stretch and recoil.

   • Location: Vocal cords.

3. Dense Irregular Collagenous Connective Tissue:

   • Structure: Randomly arranged collagen fibers.

   • Function: Strength in multiple directions.

   • Location: Dermis of the skin.

Supporting Connective Tissue: Cartilage

1. Fibrocartilage:

   • Structure: Tough, with collagen fibers.

   • Function: Resists compression.

   • Location: Intervertebral discs.

2. Elastic Cartilage:

   • Structure: Contains elastic fibers.

   • Function: Flexible and resilient.

   • Location: Outer ear.

Supporting Connective Tissue: Bone

1. Spongy Bone:

   • Structure: Lattice-like structure.

   • Function: Supports and protects bone marrow.

   • Location: Ends of long bones.

2. Compact Bone:

   • Structure: Dense and solid.

   • Function: Provides strength.

   • Location: Outer layer of bones.

Fluid Connective Tissue:

1. Blood:

   • Structure: Cells suspended in plasma.

   • Function: Transports oxygen and nutrients.

   • Location: Blood vessels.

2. Bone Marrow:

   • Structure: Soft tissue inside bones.

   • Function: Produces blood cells.

   • Location: Inside bones.

Muscle Tissue:

1. Skeletal Muscle:

   • Structure: Long, striated fibers.

   • Function: Voluntary movement.

   • Location: Attached to bones.

2. Cardiac Muscle:

   • Structure: Striated, branched fibers.

   • Function: Pumps blood.

   • Location: Heart.

3. Smooth Muscle:

   • Structure: Spindle-shaped cells.

   • Function: Involuntary movement.

   • Location: Walls of hollow organs (e.g., intestines).

Nervous Tissue:

1. Neurons:

   • Structure: Nerve cells with dendrites, axon.

   • Function: Transmit electrical signals.

   • Location: Brain, spinal cord.

2. Dendrites:

   • Function: Receive signals.

3. Glia:

   • Function: Support and protect neurons.

Types of Neurons:

1. Multipolar Neuron:

   • Function: Motor control.

   • Location: Central nervous system.

2. Pseudo-unipolar Neuron:

   • Function: Sensory functions.

   • Location: Sensory pathways.

Tissue Membranes:

1. Mucous Membranes:

   • Function: Protects and lubricates.

   • Location: Digestive and respiratory tracts.

2. Serous Membranes:

   • Function: Secretes lubricating fluid.

   • Location: Lining body cavities.

3. Synovial Membranes:

   • Function: Secretes fluid for joint lubrication.

   • Location: Joints.

SKELETAL SYSTEM

Functions:

1. Support: Provides structure and framework for the body.

2. Protection: Protects vital organs (e.g., skull protects the brain, ribs protect the heart and lungs).

3. Movement: Bones act as levers for muscles.

4. Mineral Storage: Stores calcium and phosphorus.

5. Blood Cell Production: Bone marrow produces red blood cells.

6. Fat Storage: Yellow marrow stores fat.

Components:

1. Bones: The hard, calcified tissue that makes up most of the skeleton.

2. Cartilage: Flexible tissue covering joints and providing support in some body parts.

   • Types of Cartilage:

     • Hyaline Cartilage: Provides smooth surfaces for movement, found in joints.

     • Fibrocartilage: Resists compression, found in intervertebral discs.

     • Elastic Cartilage: Provides flexible support, found in the ear.

3.     Tendons: Strong bands of connective tissue where bones attach to. It is muscle to tissue

4.     Ligaments: Holds bones together, allow some movement between bones but prevent excessive movement

Bone Histology:

1. Bone Matrix: Composed of collagen fibers and minerals like calcium.

2. Osteogenesis: The process of bone formation.

3. Bone Cells:

ORIGIN OF BONE CELLS

Connective tissue develops embryologically from mesenchymal cells

3. Osteochondral Progenitor Cells: Stem cells that give rise to bone cells. They are loated in the inner layer of perichondrium (The inner layer of the periosteum  a potential source of new osteoblasts or chondroblasts.

4. Osteoblasts: Bone-forming cells.

5. Osteocytes: Mature bone cells.

6. Osteoclasts: Cells that break down bone tissue.

Bone Anatomy:

1. Bone Shapes:

   • Long Bones: Longer than wide (e.g., femur).

   • Short Bones: Cube-shaped (e.g., wrist bones and ankle).

   • Flat Bones: Thin and curved (e.g., skull).

   • Irregular Bones: Complex shapes (e.g., vertebrae and facial bones).

2. Anatomy of a Long Bone:

   • Diaphysis: Shaft of the bone. A long, hollow, tubular shaft of the bone. Has a thick/densed layer of compact bone, a form osseous tissue.

It support the bone as it provides strength, it serves as a housing for marrow cavity, which involves blood cell production.

2. Epiphysis: Ends of the bone. Filled internally with spongy bone, another form of osseous tissue.

Red bone marrow can be seen within the spaces between the spongy bone in some long bones.

This part of the bone reduces the friction and facilitates smooth movement at joints, absorbing shock. And, since it contains the red bone marrow-Hematopoiesis occurs, which is the production of blood cells.

2. Periosteum: Outer covering. Ligaments and tendons attach to bone through the periosteum. It contains the blood vessels and nerve pathways. Responsible for bone growth in diameter.

It provides a route for nerves and blood vessels to enter the bone. It attaches muscles and tendons to the bone.

2. Marrow Cavity: A cental hollow space that is found inside the diaphysis, which is filled with yellow bone marrow in adult.

It is the site for blood cell production and fat storage. It helps maintain hematopoiesis

2. Endosteum: Lining inside the bone. A thin layer of connective tissue lining the inner surface of the marrow cavity. It is where the bone cells grow, repair, and remodel throughout life.

3. Articular Cartilage: Thin layer of hyaline cartilage covering a bone where it forms a joint (articulation) with another bone.

4. Medullary Cavity: Central cavity containing marrow.

   • Red Marrow: Produces blood cells.

   • Yellow Marrow: Stores fat.

Bone Development (Ossification):

1. Intramembranous Ossification: Direct bone formation (e.g., skull bones). It is within the membrane at centers of ossificatuion, osteoblast produce bone along the membrane fibers to form cancellous bone. The skull bones, part of the mandible (lower jaw), and the diaphysis of the clavicles (collarbones)

2. Endochondral Ossification: Bone forms by replacing cartilage (e.g., long bones). Bones of the base of the skull, part of the mandible, the epiphyses of the clavicles, and most of the remaining skeletal system.

Gross Anatomy of the Skeletal System:

Gross Anatomy

The average adult has 06 bones, the actual number of bones varies between people and decreases with age as bones become fused, bones are segregated into the axial and appendicular skeleton.

• Axial Skeleton (80 bones):

  • Skull, vertebral column, and rib cage (Thoracic cage), hyoid bone, auditory ossicles.

• Appendicular Skeleton (126 bones):

  • Upper and lower Limbs, pelvic girdle, and shoulder girdle.

  • Term, “girdle” means, “belt” or “zone” refers to the two zones where the limbs are attached to the body, These two zones are the pectoral girdle and the pelvic girdle.

The Skull:

Consists of 8 cranial bones and 14 facial bones, making a total of  bones. These bones are responsible for protecting the brain and forming the basis of the face.

• Cranial Bones, aka the cranium, encase and safeguard the brain, they feature visible ridges and lines, many of which serve as attachment points for head and neck muscles. (8 total):

  • Frontal Bone: Forehead region. Connects the two parietal bones via the coronal suture, which get its name from the Latin term for “crown” as it is where a crown or tiara would sit.

• Parietal Bones: Top sides of the skull (2). Paired bones from a major part of the skull’s top. Joined by the sagittal suture and connected to the occipital bone via the labdoid suture.

Sutural or Wormian bones may appear along the lambdoid suture. It contributes to the skull’s lateral structure with the temporal bones. it features temporal lines for the attachment of the temporalis muscle, crucial for chewing.

• Temporal Bones: Lower sides (2). Connects to the skull via squamous sutures, which are named for their overlapping, scale-like appearance. The term “temporal” originated from the observation that hair on the temples grays with age.

The temporal bones have three main regions: Squamous, tympanic, petrous.

• Occipital Bone: Back of the skull. Forms the majority of the skull’s posterior wall and base. Contains the foramen magnum for brainstem and spinal cord connection, supports the cerebellum in the posterior cranial fossae, it also features occipital condyles that articulate with the first cervical vertebra.

• Sphenoid Bone: Butterfly-shaped bone in the middle. A singe bone spanning the skull’s width, resembling a bat. It has four parts, central body, greater wings, lesser wings, and pterygoid processes. Cental body forms the sella turcica and contains sphenoidal sinuses, optic canals allow passage of the optic nerve.

Paired foramina (Rotundum, ovale, spinosum) pass blood vessels and nerves, greater wings form part of the middle cranial fossa, lateral skull wall, and posterior eye orbit, lesser wings create a ridge between cranial fossae and border the superior orbital fissure.

·       Ethmoid Bone, centrally located, porous and fragile, forms the nasal septum, part of the nasal cavity, and the medial eye orbit wall. It contains the ethmoidal sinuses, nasal conchae (Superior, middle, and inferior) increase surface area for air moistening, particle removal, and warming.

• Facial Bones (14 total):

  • Zygomatic Bones: Cheekbones (2). Anterior to the sphenoid bone, it forms the inferiolateral borders of the eye orbits, zygomatic arch is formed by the tempora process of the zygomatic bone and the zygomatic process of the temporal bone.

  • Maxillae: Upper jaw (2). Ocated anterior and inferior to the zygomatic bones and are fused medially. They form the upper jaw, supporting the upper teeth. They make up most of the hard palate, separating the oral and nasal cavities. They also contribute to the center portion of the face.

  • Nasal Bones: Bridge of the nose (2). The frontal processes of the maxillae form the bridge of the nose, the are where eyeglasses typically rest.

  • Mandible: Lower jaw. The only freely movable skull bone, located inferior to the maxillae and attaches to the temporal bone via the mandibular fossae.

  • Palatine Bones: Back of the roof of the mouth (2). Horizontal plates that fuse medialy with each other and the maxillae to form the posterior hard palate, they also have vertical plates that project superiorly, contributing to a small portion of the orbit and nasal cavity.

  • Lacrimal Bones: Inside corner of the eye sockets (2). Smallest skull bones, they contain a depression for the nasolacrimal duct (connects the orbits to nasal cavity, draining tears from the eyes into the nasal cavity)

  • Vomer: Part of the nasal septum. Forms most of the posterior nasal septum, located between rhe medial pterygoid plates of the sphenoid bone in the central nasal cavity.

  • Inferior Nasal Conchae: Inside the nasal cavity (2). One of the three scroll like coonchae in the nasal cavity, Conchae, including the inferiori nasal concha, increase the surface area within the nasal cavity.

  • Hyoid Bone: A u-shaped and crucial for speech and swallowing, it is unique as it is not directly attached to any other bone, but it is connected to the skull via muscles and ligaments. Positioned in the soft tissues of the neck, just below the mandible

Vertebral Column: consists of 26 bones, known as vertebrae. Can be divided into five regions:

• Cervical Vertebrae: C1 - C7 (neck). Located in the region of the vertebral column with the greatest range of motion, it supports and allow movement of the head, it has small bodies, making them prone to dislocations and fractures. Most cervical vertebrae have bifid (split) spinous processes. Transverse processes possess transverse foramina, allowing the vertebral arteries to extend toward the head.

• Thoracic Vertebrae: T1 - T12 (upper back). Least movable of the five regions, due to its articulation with the ribs, it protects the heart and lungs, has long spinous processes the project inferiorly, the transverse processes of thoracic vertebrae are longer than those of other regions, the first 10 thoracic vertebrae possess articular facets for the tubercles of the ribs, and then the bodies of thoracic vertebrae have articular facets for the head of the ribs

• Lumbar Vertebrae: L1 - L5 (lower back). Bear the majority of the body weight, they have massive bodies and heavy rectangular transverse and spinous processes, fractures of lumbar vertebrae are less common due to the thickness of their bodies, ruptured intervertebral discs are more common in the lumbar region than in other parts of the vertebral column.

• Coccygeal: 4 fused bones (tailbone). CO

• Sacral (S)

• Sacrum: 5 fused bones.

During development the embryo starts with about 33 or34 vertebrae, but some of these fuse to form single bones by adulthood.

Limbs and Girdles:

• Scapula (shoulder blade).

• Clavicle (collarbone).

• Humerus (upper arm bone).

• Phalanges: Finger and toe bones.

• Coxa (pelvis): Ilium, ischium, pubis.

• Femur: Thigh bone.

• Tibia: Larger lower leg bone.

• Fibula: Smaller lower leg bone.

• Patella: Kneecap.

• Tarsals: Ankle bones.

• Hind foot: Talus, Calcaneus

• Midfoot: Navicular, cuboid, 3 cuneiforms.

Depressions:

• Fossa: Shallow depression. General term for depression.

• Notch: depression in the margin of a bone

• Fovea: Little pit

• Groove or Sulcus: Deeper, narrow depression.

Openings:

• Foramen: Hole in a bone (e.g., foramen magnum in skull)..

• Meatus: Canal-like passageway (e.g., ear canal).

• Sinus

• Fissure

Processes for Joint Formation:

• Facet: Smooth, flat surface for articulation.

• Head: Rounded end of a bone.

Processes for Soft Tissue Attachment:

• Crest: Ridge of bone.

• Condyle: Rounded articular projection.

• Tubercle/Tuberosity: Small rounded projection.

• Trochanter: Large, blunt, irregularly shaped projection.

• Spinous Process: Sharp, slender projection.

Specialized Skull Regions:

• Cranial Fossae: shallow depressions within the cranial cavity that house and protect the brain.

Three cranial Fossae

• Anterior Cranial Fossa: Supports the frontal lobes. Formed by frontal bone, ethmoid bone, and lesser wings of the sphenoid bone, houses the frontal lobes of the brain.

• Middle Cranial Fossa: Supports the temporal lobes. Encompasses the area from the posterior portion of the lesser wings of the sphenoid bone to petrous part of the temporal bone, bordered by the parietal bones. tempooral lobes of the brain rest here.

• Posterior Cranial Fossa: Supports the cerebellum. Bordered anteriorly by the posterior protion of the petrous part of the temporal bone, posteriorly by the occipital bone, and laterally by the parietal bone. Contains the cerebellum and a portion of the brainstem.

• Nasal Cavity: formed by the convergence of multiple bones and has a rounded opening anteriory. Divided into right and left halves by the nasal septum, which consists of various components:

Posterior part of the nasal septum: made up of the perpendicular plate of the ethmoid bone and the vomer bone

Anterior part of the nasal septum: composed of the hyaline cartilage.

In a dried skull, the entrances to the nasal cavity appear larger than those in a living person. This is because the external nose, mainly made of hyaline cartilage, is absent in a dried skull.

The visible parts of the ecternal nose in a dried skull, are the two nasal bones and the maxilla.

Bone Development in Babies:

• Babies’ skulls have soft spots (fontanelles) where bones haven’t fully fused, allowing for flexibility during birth. Openings (foramen) and depressions (fossa) in the skull are not fully developed, making the head more malleable.

Bone Movements:

• Angular Movements: Flexion, extension, abduction, and adduction are movements involving changes in the angle between bones at a joint.

Phalanges: Fingers

The bones of the fingers w each finger typically having three phalanges (Proximal, middle and distal) except for the thumb which has two.