Chapter 4 Chapter 4 Body Basics

Body Chemistry ConceptsBody Chemistry ConceptsMatter: comprised

of an atom that contains protons and electrons

Protons: + charged particles in the nucleus of the atom

Electrons: - charged particles that surround the nucleus of an atom

Number of electrons equals the number of protons, atoms are neutral

Elements: each type of atom; under ordinary conditions, a substance that cannot be broken down into distinctive components◦Building blocks of matter

Minerals: elements that are found in the earth’s crustEssential nutrients

Ca, Fe, K

Essential ElementsEssential Elements

MoleculesMoleculesMolecule: matter that forms

when two or more atoms interact and are held together by a chemical bond

Chemical bond: attraction that holds atoms together

Definitions….Definitions….Compounds: molecules that contain

two or more different elementsSolution: evenly distributed mixture

of two compoundsSolvent: primary compound of a

solutionSolute: lesser component in a

solutionSolubility: describes how easily a

substance dissolves in liquid solvent

More definitions….More definitions….Ion: atom or group of atoms that has a

positive or negative chargeH+: hydrogen ion chemical formulaElectrolytes: ions that conduct electricity

when they are dissolved in a solutionAcids: substances that donate hydrogen

ionsBases: substances that accept hydrogen

ionspH: measure of the acidity or alkalinity

of a solution

And more definitions….And more definitions….Chemical reactions: process that

changes that atomic arrangement of molecules

Digestion: process by which large ingested molecules are mechanically and chemically broken down

Salt: substance when acid combines with a base

Metabolism: the sum of all chemical reactions occurring in living cells

Basic Physiology ConceptsBasic Physiology ConceptsAnatomy: the scientific study of

cells and other body structuresPhysiology: scientific study of

the functioning of cells and other body structures

Human Human CellCell

Organelles: structures in cells that perform specialized functions

Nucleus: Organization and expression of the genetic material (DNA)

Plasma membrane: Movement of substances into and out of the cell

Ribosome: protein synthesisMitochondrion: Site of ATP (high-

energy molecule) synthesis

Human CellHuman Cell

Cells cont…Cells cont…Tissues: collection of cells that

perform a specific functionEpithelial tissues: cells that line

every body surface (skin, inside of blood vessels)

Connective tissues: type of cells that hold together, protect and support organs (fat, bone and blood)

Organization of the human Organization of the human bodybody

Cell Tissue

Organ System

DefinitionsDefinitionsOrgan: collection of tissues that

perform a specific functionOrgan system: Collection of

organs that work together to perform a major function

Homeostasis: relatively constant internal environment in the body that is critical for good health and survival

Definitions…Definitions…Arteries:

vessels that carry blood away from the heart

Capillaries: smallest blood vessels

Veins: vessels that return blood to the heart.

Cardiovascular SystemCardiovascular System

•Heart•Blood vessels•Blood•Circulation of blood throughout the body

Respiratory SystemRespiratory System

Exchange of O2 and CO2

Blood transports the respiratory gases, with hemoglobin carrying the oxygen

The heart pumps oxygen-poor blood to the lungs

–In the lungs it picks up O2and drops off CO2

–In the tissues, cells pick up CO2and drop off O2

–Gases diffuse down pressure gradients in the lungs and the tissues

Gas exchange in the body

Hemoglobin is a protein in red blood cells

–It carries most of the oxygen in the blood

O2 loaded in lungs

O2 unloaded in tissues

Heme group Iron atom

Polypeptide chain

O2

O2

Hemoglobin helps buffer the pH of blood and carries some CO2

Most CO2 in the blood combines with water to form carbonic acid◦–The carbonic acid breaks down to

form H+ions and bicarbonate ions ◦–These help buffer the blood

Most CO2 is transported to the lungs in the form of bicarbonate ions

LymphatiLymphatic Systemc System

Defense and immunity against infectious agents, fluid balance, WBC production, absorption of fat-soluble nutrients from intestinal track

Other parts:◦ Lymphatic fluid◦ WBC◦ Primary lymphoid

organs Bone marrow and

thymus◦ Secondary lymphoid

organs Spleen, lymph nodes

Lymphatic SystemLymphatic System

Lymphoid CellsLymphocytes are the main cells

involved in the immune response◦ Two main varieties:

T cellsB cells

T cells and B cells protect the body against antigens◦ Antigen – substances that can stimulate

the immune systemSelfNonself

Bacteria and their toxins; virusesMismatched RBCs or cancer cells

LymphocytesT cells

◦Manage the immune response◦Attack and destroy foreign cells

B cells◦Produce plasma cells, which secrete

antibodies◦Antibodies immobilize antigens

Other Lymphoid CellsMacrophages – phagocytize

foreign substances and help activate T cells

Dendritic cells – spiny-looking cells with functions similar to macrophages

Reticular cells – fibroblast–like cells that produce a stroma, or network, that supports other cell types in lymphoid organs

ThymusThe thymus differs from other

lymphoid organs in important ways◦It functions strictly in T lymphocyte

maturation◦It does not directly fight antigens◦The stroma of the thymus consists of

starshaped epithelial cells (not reticular fibers)

◦These epithelial cells (thymocytes) secrete the hormones that stimulate lymphocytes to become immunocompetent

Thymus

SpleenLargest lymphoid organ, located

on the left side of the abdominal cavity beneath the diaphragm

It is served by the splenic artery and vein, which enter and exit at the hilus

Functions:◦Site of lymphocyte proliferation◦Immune surveillance and response◦Cleanses the blood

Additional Spleen FunctionsStores breakdown products of

RBCs for later reuseSpleen macrophages salvage and

store iron for later use by bone marrow

Site of fetal erythrocyte production (normally ceases after birth)

Stores blood platelets

Spleen

Lymphoid TissueDiffuse lymphatic tissue – scattered

reticular tissue elements in every body organ◦ Larger collections appear in the lamina propria

of mucous membranes and lymphoid organsLymphatic follicles (nodules) – solid,

spherical bodies consisting of tightly packed reticular elements and cells◦ Germinal center composed of dendritic and B

cells◦ Found in isolation and as part of larger

lymphoid organs

Tonsils

Simplest lymphoid organs; form a ring of lymphatic tissue around the pharynx

Location:Palatine tonsils – either side of

the posterior end of the oral cavityLingual tonsils – lie at the base of

the tonguePharyngeal tonsil – posterior wall

of the nasopharynxTubal tonsils – surround the

openings of the auditory tubes into the pharynx

Urinary SystemUrinary SystemElimination of

salts, water, and wastes; maintenance of fluid balance

Muscular SystemMuscular System

Movement and stability of body

Facts about musclesMuscle: A tissue composed of fibers

capable of contracting to effect bodily movement

There are about 650 muscles in the human body.

Every person has a unique tongue print.

Hiccups are spasm of the diaphragm.

Types of Muscles Skeletal muscles: Attached to bones. (what

happens when you extend your arm?)

Smooth muscle: Surround organs, tubes,

eg. stomach, urinary bladder, blood vessels. Contract propels content through organs (eg. expel urine).

Cardiac muscles: Heart muscle makes your

heart pump blood.

Skeletal SystemSkeletal System

Facts about skeletal system Do we have more bones when we are a baby or when we are all

grown up? Baby has 305 bones and an adult has 206 bones. This is because as

we grown some of our bones join together to form one bone.

The longest bone in our bodies is the femur (thigh bone).

The smallest bone is the stirrup bone inside the ear.

Each hand has 26 bones in it.

our nose and ears are not made of bone; they are made of cartilage, a flexible substance that is not as hard as bone.

Differences between males and females: Males and females have slightly different skeletons, including a different elbow angle. Males have slightly thicker and longer legs and arms; females have a wider pelvis and a larger space within the pelvis, through which babies travel when they are born.

Five main functions of the human skeletonProtect the vital organs we talked about last

week

2. Give us shape

3. Allow us to move because our muscles are attached to our bones

4. Storage of nutrients such as calcium and silicon

5. Formation of blood cells

Nervous SystemNervous SystemThought

process, regulation and coordination of many body activities, detection of changes in external and internal environments

Basic nerve structure

3 types of nerve structures

sensory neurone relay

neurone

motor neurone

Endocrine SystemEndocrine SystemMain Function:

It releases hormones into the blood to signal other cells to behave in certain ways. It is a slow but widespread form of communication.

Regulation and coordination of many body activities, including growth, nutrient balance, and reproduction

Endocrine System (Endocrine System (Pituitary Gland)Function: It secretes nine hormones

that directly regulate many body functions and controls functions of other glands.

Disorders: Too much growth hormones (GH) in early childhood can result in a condition called gigantism. Too little GH can result in Pituitary Dwarfism.

Endocrine (thyroid gland)Function: plays a major role in

regulation the body’s metabolism.

Disorders: If the Thyroid Gland produces too much Thyroxin, it can cause a condition known as Hyperthyroidism. If too little thyroxin produces it is called Hypothyroidism.

Endocrine (pancreas)Function: The Insulin and Glycogen

in the Pancreas help to keep the level of glucose in the blood stable.

Disorders: When the Pancreas fails to produce or properly use Insulin, it can cause a condition known as Diabetes Mellitus.

Endocrine (Adrenal Gland)Functions:

-The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress.-Also regulates kidney function.

Endocrine (ovaries)Functions:

◦Pair of reproductive organs found in women that produce eggs.

◦Also secrete estrogen and progesterone, which control ovulation and menstruation.

Endocrine (testes)Functions:

◦Pair of reproductive glands that produces sperm.

◦Also secrete Testosterone to give the body its masculine characteristics.

Integumentary SystemIntegumentary SystemFunctions of skinProtection Cushions and insulates and is waterproof

Protects from chemicals, heat, cold, bacteria

Screens UV

Synthesizes vitamin D with UV

Regulates body heatPrevents unnecessary water loss

Sensory reception (nerve endings)

DermisStrong, flexible connective tissue:

your “hide”Cells: fibroblasts, macrophages, mast

cells, WBCsFiber types: collagen, elastic, reticularRich supply of nerves and vesselsCritical role in temperature regulation

(the vessels)Two layers

◦ Papillary – areolar connective tissue; includes dermal papillae

◦ Reticular – “reticulum” (network) of collagen and reticular fibers

Burns

First-degree(epidermis only; redness)

Second-degree(epidermis and dermis,with blistering)

Third-degree(full thickness, destroying epidermis, dermis, often part of hypodermis)

Skin Cancer

Nails

HairFunctions of hair

◦Warmth – less in man than other mammals

◦Sense light touch of the skin◦Protection - scalp

Parts◦Root imbedded in skin◦Shaft projecting above skin surface

Make up of hair – hard keratin

Hair cont…Types of hair

◦ Vellus: fine, short hairs◦ Intermediate hairs ◦ Terminal: longer, courser hair

Hair color◦ Amount of melanin for black or brown;

distinct form of melanin for red◦ White: decreased melanin and air bubbles

in the medulla◦ Genetically determined though influenced

by hormones and environment

Reproductive SystemReproductive System

Procreation

ReproductionPrimary sex organs (gonads) –

testes in males, ovaries in females◦Gonads produce sex cells called

gametes and secrete sex hormonesAccessory reproductive organs –

ducts, glands, and external genitalia

Sex hormones – androgens (males), and estrogens and progesterone (females)

Digestive SystemDigestive System

Digestion and absorption of nutrients

Digestion Phases and structures

Phases◦Ingestion◦Movement◦Digestion◦Absorption◦Further

digestion

Structures•Mouth•Oral Cavity•Pharynx•Esophagus•Stomach•Duedenum •Jejenum•IIleum•Cecum•Ascending colon•Transverse colon

MouthMouthMechanical

digestionSenses taste

and textureSalivary glands

EsophagusEsophagus A tube that extends

about 10 inches from the back of the mouth, the pharynx, to the top of the stomach

Epiglottis: flap of tissue that folds down over the windpipe to keep food from entering the respiratory system

Gastroesophageal sphincter: section of esophagus next to stomach that controls the opening to the stomach

StomachStomachHolds up to four

cups of foodChyme: mixture

of gastric juices and partially digested food

Pyloric sphincter: controls the rate in which chyme is released into the small intestine

Stomach usually empties in about 4 hours

Stomach cont…Functions

◦ Mix food◦ Reservoir◦ Start digestion of

Protein Nucleic acids Fats

◦ Activates some enzymes

◦ Destroy some bacteria

◦ Makes intrinsic factor – B 12 absorption

◦ Destroys some bacteria

◦ Absorbs Alcohol Water Lipophilic acid B 12

Small intestineSmall intestine6 1/2 feet

longVilla3 sections

◦Duodenum◦Jejunum◦Ileum

Villi in small intestine

Small intestine cont… Secretes digestive

enzymes◦ Peptidases

Amino- Di- Tri-

◦ Sucrases◦ Maltase◦ Lactase◦ Saccharidases

Di- Tri-

◦ Lipase◦ Nucleases

•Requires pancreatic enzymes & bile to complete digestion

Large Large intestineintestine

Regions◦ Cecum – Appendix◦ Colon

Ascending Transverse Descending

◦ Rectum◦ Anal canal

Chyme becomes feces

Feces FormationChyme dehydrated to form fecesFeces composition

◦Water◦Inorganic salts◦Epithelial cells◦Bacteria◦Byproducts of digestion

Defecation◦Peristalsis pushes feces into rectum◦Rectal walls stretch

Accessory OrgansAccessory Organs Play role in digestion even

though chyme does not move through them

Liver: ◦ process and stores nutrients◦ Makes cholesterol◦ Uses lipids to make bile

Gallbladder◦ When food and fat are in the

duodenum, the small intestine send signal for gallbladder to release bile into duodenum

Pancreas◦ Produces and secretes most

of the enzymes that break down carbs, protein, and fat in GI tract

◦ Secretes biocarbonate ions that neutralizes HCL in chyme

Liver cont…Liver: Functions

◦ Makes bile Detergent – emulsifies

fats Release promoted by:

Vagus n. CCK Secretin

Contains Water Bile salts Bile pigments Electrolytes Cholesterol Lecithin

More Liver…yuck◦ Detoxifies/removes

Drugs Alcohol

◦ Stores Gycolgen Vitamins (A, D, E, K) Fe and other minerals Cholesterol

◦ Activates vitamin D◦ Fetal RBC production◦ Phagocytosis◦ Metabolizes absorbed food molecules

Carbohydrates Proteins Lipids

Dual blood supply◦ Hepatic portal vein

Direct input from small intestine◦ Hepatic artery/vein

Direct links to heart