anatomy mid term

Gross Anatomy

Study of large body structures

• visible to naked eye

• Ex. Heart, skull, foot

Systemic Anatomy

Study of an entire system within the body

• organs working for a function

• Ex. Cardiovascular system, Resp system

Microscopic anatomy

Study of very small structures that may not be seen by the unaided eye

Includes:

• cytology: the study of individual cells

• Histology: the study of tissues

Chemical Level

• Most basic level

• atoms (smallest units of matter) come together to form molecules

• Ex. Water molecules (H2O) are formed when 2 hydrogen atoms (H) combine with one Oxygen atom (O)

Cellular Level

• Individual cells

• Smallest units of life

• Basic unit of structure and function

Tissue Level

• Cells of the same kind come together to form tissues

• Defined as groups of similar cells coming together to perform a common function

• Four main tissues types in the body:

• 1) Epithelial Tissue

• 2) Connective Tissue

• 3) Muscle Tissue

• 4) Nervous Tissue

Organ Level

Organs are composed of two or more tissues

Ex: bladder

• organ composed of smooth muscle allows expansion in order to hold urine

  • Nervous tissue: to control urination

  • Epithelial Tissue:

  • Connective Tissue: reinforces the walls of the bladder

Organ system

A number of related organs working together to accomplish a common function

Ex.

• Circulatory system: heart, arteries, veins all work together to circulate blood providing cells with oxygen and nutrients

Organism

All of the organ systems of the body come together performing necessary functions for life

• ex. Respiratory system, cardiovascular system, digestive system, nervous system, reproductive system all come together to form a functional living human being

Matter

Anything that has mass and occupies space

• Stuff the fills the universe

• Composed of elements

• Elements are made up of atoms

Atoms

The smallest unit of an element

• atoms that make up a particular element are identical

• Ex. All atoms that are found in the element oxygen are the exact same

Atomic structure

• all atoms have protons, neutrons, and electrons

• The protons (+) and the neutrons are found in the nucleus of the atom

• The electrons (-) are found outside he nucleus

• If the atom is neutral the number of protons=number of electrons

  • Total charge of the atom is equal to 0

• An atom that gains or looses electrons is no longer neutral and is called an ion

Water

• Most living cells are 60-80% water

• Classified as a polar molecule

  • Polar molecules are defined as having a partial positive and a partial negative charge

• Key functions of water include

  • Ability to act as a solvent

    • Ex. Salt or sugar can be dissolved in water

  • In chemical reactions

  • Maintaining body temperature

  • Lubricates joints and fills area around organs

Acids

Dissociate when placed in water

• release H+ ions

• Ex. HCl → H+ + Cl-

• The more HCl that is added to water, the more H+ will be present following dissociation

• The greater the amount (concentration) of H+ in the solution, the lower the pH of the solution

• Lower pH means a greater acidity

Bases

Disssociate in water also

• Release OH- ions

• Ex. NaOH → Na+ + OH-

• The OH- that is generated from the dissociation of NaOH binds to H+

• The greater the amount (concentration) of OH- in the solution, the greater the pH of the solution

• Higher pH means that the solution is more basic

Neutral pH

7

• the amount of H+ in solution is equal to the OH- in solution

Acidic pH

0-6

• 0 is most ___ and 6 is the least

Basic pH

8-14

• 8 is the least ___ and 14 is the most

Carbohydrates

Sugars and starches

Contain carbon, hydrogen, and oxygen in a 1:2:1 ratio

Classified as either monosaccharides, disaccharides or polysaccharides

Monosaccharides

• One sugar

• Basic building blocks of carbs

• Ex. Glucose, fructose

Disaccharides

• Two monosaccharides covalently bound to one another

• Ex. Sucrose

• Sucrose is what we know as table sugar

Polysaccharides

• Many monosaccharides bond together covalently

• Ex. Glycogen (animals) and starch (plants), both long chains of glucose

Proteins

Made up of amino acids (20 different kinds of amino acids)

Contain carbon, oxygen, hydrogen and nitrogen

Have an enormous variety of different functions

Structural Proteins

Collagen (in skin) actin (muscles)

Cell function Proteins

Hemoglobin (oxygen transport), cytokines (cell to cell messengers)

Peptides

Amino acids bound together form ___

• Dipeptides:

  • 2 amino acids bound together

• Polypeptides

  • Many amino acids bound together

• One or more polypeptides folded into a characteristic shape

Lipids

Fancy name for fats

Most common lipids found in the human body are glycerides

• obtained through diet

• Glyceride is made of glycerol and fatty acids

  • Monoglycerides:

    • Glycerol and one fatty acid

  • Diglycerides:

    • Glycerol and two fatty acids

  • Triglycerides:

    • Glycerol and three fatty acids

Phospholipids

Composed of a diglyceride and a phosphate group

Two fatty acids Triglycerides tails (attached to the glycerol) are non-polar

• non-polar is also called hydrophobic and means not water soluble

The phosphate ‘head’ group (attached to the other side of the glycerol) is polar

• polar is also called hydrophilic and means ‘water loving’ or water soluble

Steroids

Produced from cholesterol

Ex. Includes the hormones estrogen and testosterone

Nucleic Acids

Composed of nucleotides

Made up of carbon, nitrogen, oxygen, hydrogen and phosphorous

Ex: DNA and RNA

Nucleotides

Basic building blocks of DNA and RNA composed of:

• a phosphate group

• A monosaccharide

  • Ribose sugar in RNA

  • Deoxyribose sugar in DNA

• An organic base

DNA

Double stranded helix

Deoxyribose sugar In each nucleotide

Composed of Adenine, Guanine, Cytosine, and Thymine

• Adenine base pairs with thymine forming 2 hydrogen bonds

• Cytosine base pairs with guanine forming 3 hydrogen bonds

The main component of chromosomes:

• Encodes genes

• Used to produce RNA

RNA

A single stranded molecule

Ribose sugar in each nucleotide

Composed of Adenine, Guanine, Cytosine, and Uracil

• adenine base pairs with uracil forming 2 hydrogen bonds

• Cytosine base pairs with guanine forming 3 hydrogen bonds

Made from DNA

• Used to produce protein

ATP

Adenosine tri-phosphate

Made of ribose sugar, adenine and three phosphate groups

Bonds between each of the phosphate groups are very high energy

• Breaking these bonds releases energy so that it may be used to power processes within the cell

• ATP becomes ADP when one of the bonds is broke removing a phosphate group

• ADP becomes AMP when another phosphate is removed

Phospholipid Bilayer

A continuous layer: forms the bulk of the membrane structure

Consists of polar phosphate + head group that faces the inside of the cell and he outside of the cell → polar groups have favourable interactions with water

Also consists of two non-polar tails that are attached to the phosphate head group

• point toward the interior of the plasma membrane

• Protected from water because the are non-polar

Cholesterol is also present in the plasma membrane of humans

• stabilizes the membrane especially as temperature increases/decreases

Membrane proteins

• transmembrane proteins are embedded in the plasma membrane and pass all the way through the membrane

• Peripheral membrane proteins are attached to either the cytoplasmic surface of the membrane or the extracellular surface

• Membrane proteins function as channels, receptors, and enzymes among other things

Membrane Carbohydrates

Only located on the outer surface of the membrane

• functions in cell to cell recognition

Attached to either:

• Protein: called glycoprotein

• Lipid: called glycolipid

Microvilli

Folds of the plasma membrane

Serve to increase surface area

• Especially important in cells where nutrient absorption occurs

Cytosol

Semi-transparent, viscous fluid

Bathes the organelles inside of the cell

Water is the main component

Also contains:

• Dissolved ions→Na+, Cl-,K+,Ca+

• Suspended carbohydrates ad lipids

• Melanin granules in certain cells

Ribosomes

Non-membranous

Composed of rRNA and protein

Responsible for protein synthesis

Can be located free in the cell or attached to the endoplasmic reticulum

Centrosomes

Are a region located near to the nucleus

Contains a granular looking matrix and 2 centrioles

Centrioles

Small, cylindrically shaped organelles

Composed of microtubules

Located perpendicular to one another

Function to direct the movement of chromosomes during cell division

Cytoskeleton

Determines/holds cell shape

Used to anchor organelles in place

Used to move materials throughout the cell

Composed of 3 types of protein rods located in the cytosol

Microfilments

Composed of actin

Thinnest component of the cytoskeleton

Important for muscle contraction, cell movement, maintenance of cell shape

Intermediate filaments

Composition differs based on tissue type

Works to support the cytoplasm

Microtubles

Composed of tubulin

Hollow tubes

Largest component of the cytoskeleton

Structural function to anchor and move organelles

Compromises centrioles, flagella, cilia, and the spindle apparatus used during cell division

Mitochondria

• surrounded by a double membrane

• Power house of the cell

• Works to produce ATP → primary energy currency of the cell

• Contains DNA, RNA, protein, and water

Rough Endoplasmic Reticulum

Appears rough because it has ribosomes attached to its surface

Ribosomes work to synthesize certain proteins here

Smooth Endoplasmic Reticulum

Appears smooth bc no ribosomes found

Functions to:

• store calcium

• Detoxify substances (drugs, alcohol)

• Synthesizes lipids

Golgi Apparatus

Stacks of membranous disks

Function to modify newly synthesized proteins

• Adds carbohydrate groups to these proteins

  • Form glycoproteins

• Packages protein into vesicles that then carry protein to:

  • Cell membrane

  • Lysosomes

  • Be secreted to the extracellular environment

Nucleus

Control centre of the cell

• surrounded by a double membrane that contains pores

• The outermost membrane is continuous with the rough ER

• Typically one nucleus per cell

  • Some cells contain multiple nuclei

• The nucleus is located inside of the nucleus

  • Consists of DNA, RNA, and proteins

  • It is not separated from the nucleus by a membrane

  • Site of ribosome assembly

Chromosomes

Composed of DNA and Histone proteins

Found in 2 forms in the nucleus

• thread-like and dispersed:

  • Will be found this way in cells that are not actively dividing

• Coiled/Condensed:

  • Individually visible chromosomes

  • Thicker than thread-like chromosome structure

  • Will be found this way in a cell that is actively dividing

Interphase

Duplicates cell content to make enough for two cells

Mitotic Phase

Consists of:

• Mitosis

• Cytokinesis

G1 Phase

Lasts 8-10 hours

Period of intense growth and metabolism

At the end of G1 centrosomes replicate

Any cell that will not divide again will remain in G1 phase

• Ex. Include neurons and muscle cells

  • Referred to as remaining in the G0 phase

• Cells that are destined to divide will enter into S phase

S Phase

Lasts 6-8 hours

During this stage the DNA is replicated making identical copies of each chromosome

Replicates are called sister chromatids → attached to one another by the centromere

Ensures that each daughter cell will receive a complete set of chromosomes

Kinetochore protein attaches to each centromere

• forms the kinetochore

  • A protein/DNA complex that is attached to the centromere of one chromosome

  • Occurs before mitosis and meiosis

G2 Phase

Lasts 4-6 hours

The final phase of interphase before the cells begins mitosis

Period of growth and metabolism

Enzymes and other proteins needed for cell division are produced

Each chromosome now has 2 sister chromatids attached to one another at then centromere

Prophase

Chromatin condenses and becomes visible

Nuclear membrane disappears

Nucleoli disappear

Centrosomes move to opposite poles of the cell

The spindle apparatus begins to form at the centromere

• Kinetochore proteins attach to spindle microtubules → called kinetochore microtubules

• The spindle apparatus moves the chromosomes to the equator of the cell

Metaphase

Each chromosome consists of 2 sister chromatids line up at the cell equator → called the metaphase plate

46 chromosomes in a straight line down the centre of the cell

Anaphase

The Kinetochores separate from one another

• pulls the sister chromatids apart from one another

• 46 sister chromatids then migrate to each pole

• Cytokinesis begins

Telophase

the spindle apparatus disassembles

Chromosomes uncoil forming chromatin once again

Nucleoli and the nuclear membrane reappear

Cytokinesis is completed

Mitosis ends and the cell enters G1 of interphase

There are now two identical daughter cells

Meiosis 1

Separates homologous pairs reduces the cell from diploid to haploid

1×46 duplicated chromosomes → 2×23 duplicated chromosomes

Meiosis 2

separates sister chromatids from one another

2 cells with 23 chromosomes each divide giving 4 cells with 23 chromosomes each

The stages are identical to the stages of mitosis but in a haploid cell

Prophase 1

Most complex phase in all of meiosis

Homologous pairs match up side → called synapsis

• allows them to separate into two different daughter cells

Four chromosomes arranged in a line

• 2 sister chromatids from one member of the homologous pair and 2 sister chromatids from the other → called crossing over

Metaphase 1

Tetrads align on the metaphase plate

Sister chromatids remain attached at the centromere

Microtubules are attached to the kinetochore

Anaphase 1

Homologous pairs separate from one another

Each pair moves to opposite poles of the cell

• sister chromatids still remain attached at the centromere

Telophase 1

Chromosomes arrive at the poles of the cell

Each pole of the cell now has haploid chromosome set

• Sister chromatids still remain attached at the centromere

Cytokinesis 1

Overlaps with telophase 1

Forms two haploid daughter cells with two sister chromatids per chromosome

Fertilization

Haploid sperm and haploid oocyte come into contact with one another forming a diploid zygote

• takes approximately 24 hours to complete

Pre-embryonic Development

Takes place in the first two weeks following fertilization

Series of developmental occurrences leading up to the zygote becoming an embryo

The diploid zygote begins as a single cell and divides by mitosis to produce many cells → cleavage divisions

• these divisions increase the number of cells, producing a solid ball of 16-32 cell called a morula

  • Each cell is called a blastomere

  • The overall size of the morula is the same as the zygote but instead of one cell, there are many small cells

Gestation

As the morula divides further, cells rearrange themselves and a blastocyst is produced

• the blastocyst has a fluid filled cavity called a blastocoele (blastocyst cavity)

  • Forms ~5 days post-fertilization

• Composed of:

  • Trophoblast cells that surround the blastocyst and eventually become the chorion

    • Provides nourishment to the developing embryo

  • An embryoblast which will become the embryo

Implantation

the attachment of the blastocyst to the endometrium of the uterus

• occurs 5-7 days post-fertilization

• The embryoblast develops into the embryonic disk following ____

• The embryonic disk consists of the:

  • Epiblast layer

  • Hypoblast Layer

Epiblast Layer

Part if the embryonic disk

• will give rise to the fetus

Hypoblast layer

Part of the embryonic disk

• will give rise to the yolk sac

Ectoderm

Will go on to form the nervous system and the epidermal layer of the skin

Develops from Epiblast layer

Mesoderm

Will go on to form the muscle, bone, blood vessels and the dermis

Developed from the Epiblast layer

Endoderm

Will go on to form the epithelial lining of he digestive tract, respiratory tract, urinary tracts, reproductive tract and the associated glands

Embryonic Development

Occurs from week 3 to week 8 post fertilization

Epiblast layer develops into 3 germ layers

From week 4 to 8 post-fertilization

• all major organ systems have completely developed

• The heart begins to beat

• The brain begins to develop

• The limb buds begin to differentiate

Amnion

Embryonic Membrane

• forms from Epiblast layer

• A fluid filled cavity that acts to surround and cushion the developing embryo and fetus from bumps and other disturbances

Yolk Sac

Embryonic Membrane

• forms from the Hypoblast layer

• Produces the early blood cells and the germ cells

Chorion

Embryonic Membrane

• forms from trophoblast cells

• Becomes the fetal portion of the placenta

• Surrounds all of the embryonic membranes

Allantois

Embryonic Membrane

• an out pocketing of the yolk sac

• Goes on to form the umbilical cord and the urinary bladder

Fetal Development

Occurs from the 9th week to the 40th week

• referred to as the fetal period

• period of growth and maturation of organs

Tight Junctions

Membrane junction

Protein molecules in the cell membrane fuse together

Serve to prevent substances from passing in between cells

Desmosomes

Membrane junction

Loose attachments

Use linker proteins to join adjacent cells

Gap Junction

Membrane junction

Protein channels that connect adjacent cells

Allow direct communication between cells

Allow substances to pass from the inside of one cell to the inside of another

Extremely important in smooth muscle and cardiac muscle cells

Epithelial Tissue

Found on all of the body surfaces and lines f the body cavities

An a vascular tissue → lacks blood vessels

Cells that form epithelial tissue have one free membrane

• sit on top of a basement membrane

Held together by tight junctions

Reproduce via Mitotic division

Glands located here are formed from glandular epithelium

• Ex. Salivary glands

• The major tissue of any glands is epithelial tissue and the sub-type is glandular epithelium

Classified based on:

• he number of cell layers and the shape of the epithelial cell

Simple Epithelium

A single cell layers with one free surface

Sits atop a basement membrane

Stratified epithelium

Several cell layers with one free surface

The basal/bottom-most layer sits atop a basement membrane

Pseudostratified epithelium

Appears as more than one layer but all cells really do sit on top of the same basement membrane Held together→ a single cell layer

Cuboidal

Cube-shaped cells

specialized for secretion and absorption

Columnar

Column-shaped cells

Specialized for secretion and absorption

Squamous

Irregularly shaped, scale-like cells

Specialized for secretion and absorption

Transitional

Stratified cell layer but the appearance varies with stretching

• ex: cuboidal cells in the bladder appear columnar when the bladder is stretched

Exocrine glands

Secreted products onto a surface or into a cavity

Either single-celled or multicellular

• single-celled

  • Ex. Goblet cells

    • Secrete mucous into a cavity

    • In digestive, urinary, reproductive and respiratory tracts

• Multi-cellular

  • Have ducts→passageways

  • Secretions enter ducts

  • Sudorifierous glands produces sweat

  • Sebaceous glands produce sebum (oil)

  • Salivary glands produce saliva

Endocrine glands

Ductless

Secretions are called hormones

Release hormones directly into blood

Ex. Thyroid gland secretes thyroid hormone

Epithelial Function

1. Protection

• stratified squamous epithelium

• Skin provides a barrier that keeps microorganisms out of the body

2. Secretion

• glandular epithelium

• Secretion of lubricants, sweat, etc

3. Control of Permeability

• simple epithelium

• Found at sites where exchange of material occurs

  • Ex. Absorption of digested nutrients

  • Kidney, intestine, capillaries

Connective Tissue cells include

Blasts: form and secrete the matrix → example: osteoblasts

Cytes: maintain the matrix→ ex. Osteocytes

Clasts: breakdown the matrix → ex. Osteoclasts

*osteo indicates that these are cells in the bone

Matrix

Extracellular: surrrounds the cells of the connective tissue

Provides the connective tissue with its characteristics

The matrix has 3 primary components:

• Protein fibers:

  • Collagen protein provides strength

  • Elastin protein provides stretch and recoil

• Ground substances:

  • Unstructured material located between the cells

  • Contains fibers

  • Ex. Chondroitin sulfate And hyaluronic acid

• Water

Primary Characteristics of connective tissue

• Highly vascular with some exceptions

  • Cartilage is an avascular connective tissue

• A lot of the extracellular matrix

  • Keeps the cells far apart from one another

• Primary function is to support and connect the tissues in the body