The Human Body Part II Chapters 37-39. The Respiratory System Ch. 37-3 Respiration is the process by which oxygen & carbon dioxide are exchanged between

The Human Body Part II

Chapters 37-39

The Respiratory SystemCh. 37-3

Respiration is the process by which oxygen & carbon dioxide are

exchanged between cells, the blood, and air in the lungs

• The Human Respiratory System:– Exchanges oxygen and CO2 between the

blood, air, and tissues


• The Respiratory System Consists of:– Nose, Pharynx ,Trachea, Bronchi, Lungs

• How it works: – Air moves from the pharynx into the trachea– Air passes from the trachea into two large passageways called

the bronchi (singular= bronchus)– Each bronchus leads into one of the lungs– Within each lung, the bronchus subdivides into smaller

passageways called the bronchioles– Bronchioles continue to subdivide until they reach tiny air sacs

called alveoli– Oxygen crossed over from the alveolus into thin capillaries and

the blood stream– CO2 crosses over from the blood back into the alveolis to be

disposed of as waste


• Generally speaking, the brain controls breathing• The diaphragm, located at the bottom of the chest cavity,

contracts and allows air to rush into the lungs• When the diaphragm relaxes, air is forced back out of

the lungs• The rate of breathing is controlled by the level of CO2 in

the blood • The level of CO2 is measured by the medulla

oblongata in the brain• As CO2 levels rise the medulla oblongata sends nerve

impulses to the diaphragm resulting in the contractions that make us breath in and out.


• Tobacco smoke harms the respiratory system• Tobacco smoke contains: nicotine, tar, and

carbon monoxide– Nicotine is a stimulant that increased the heart rate

and blood pressure– Tar contains substances that cause cancer– Carbon monoxide is a poisonous gas that blocks the

transport of oxygen

• Smoking can also cause Emphysema

Food and NutritionCh. 38-1

• The energy to perform actions, as well as the materials from which body cells and tissues are made comes from food

• The energy available in foods can be measured by calories– The # of calories you need each day depends on your

size & level of activity

• Nutrients are substances in food that supply energy and raw materials the body uses for growth, repair, and maintenance


• Carbohydrates are the main source of energy for the body– they include:– Sugars, starches, and fiber

• Fatty acids form fat which is needed to make cell membranes and certain hormones

• Proteins are formed by amino acids and are needed for growth and repair of the body

• Many proteins are also hormones


• Vitamins are organic molecules that help regulate the body

• Minerals are inorganic molecules that perform vital functions in the body– EX: Calcium & iron


• The Food Guide Pyramid can help people select a balanced diet– Classifies food into 6 groups– Foods at base of pyramid should make up

major portion of your diet– Foods at top of pyramid should be consumed

in small amounts

The Process of Digestion Ch. 38-2

• The function of the digestive system is to break down food into simpler molecules that can be absorbed & used by the cell

• Human digestive system includes:– Mouth, pharynx, esophagus, stomach, small

intestine, large intestine, salivary glands, pancreas, and liver

– Digestions starts in the mouth


• The teeth tear & crush food• Salivary glands secrete saliva:

– Amalyse is enzyme found in saliva that breaks chemical bonds between the sugar monomers in starches

– This begins process of chemical digestion

• From the mouth, food passes through the pharynx into the esophagus (passage that carreies food between the pharynx and the stomach)


• Food from the esophagus empties into the stomach

• Glands in the stomach produce an acid and the enzyme pepcin – Stomach churning, along with the acid and

enzyme breaks down food into a soft partially digested mixture called chyme

• Chyme passes into the small intestine (where most chemical digestion and absorption of food occurs)


• Enzymes from the pancreas help digest starch, protein and fat

• A liquid called bile from the liver helps break up fat droplets

• Nutrients are absorbed through the lining of the small intestines– Villi (small fingerlike projections) found in the

small intestines increase the surface are of the small intestines and aide in absorbtion


• Chyme next enters the large intestine where water is removed from digested material

• After most of the water has been removed, remaining waste is passed out of the body

• Digestive Disorders include:– Peptic ulcers= caused by bacteria– Diarrhea= when too little water is removed– Constipation= when too much water is removed

The Excretory SystemCh. 38-3

• The function of the excretory system is to help maintain homeostasis by removing wastes– Wastes like CO2 and urea are produced

during normal metabolism– The main organs of excretory system are

the kidneys:• They remove waste products from blood, maintain

blood pH, and control water content of blood


• 2 kidneys are located in the lower back:– Blood containing waste enters kidneys– Both useful substances and wastes are removed

from the blood by filtration– Some of the substances are later returned to the

blood– Wastes are excreted– The purified blood leaves the kidneys and returns to

circulation– The fluid that remains is called urine– which contains

urea, excess salts & other substances


• A tube called the ureter leaves each kidney and carries urine to the bladder (a saclike organ that stores urine)

• Urine passes from the body through a tube called the urethra.

• Kidneys are controlled by hormones and concentration of the blood

• A person can survive with one kidney– If both kidneys fail, a person must undergo dialysis to

survive– Dialysis purifies blood by passing it through a filtering

machine

The Endocrine SystemCh. 39-1

• The endocrine system consists of gland that release hormones into the bloodstream– Hormones are chemicals released from one area of the body

that travel throughout the body to affect cells elsewhere– Hormones bind to chemical receptors on cells called target

receptors

• The endocrine system is made up of glands – A gland is an organ that releases a secretion or hormone– There are endocrine and exocrine glands– Exocrine glands release secretions directly into tissues and

organs• EX: Sweat glands


• There are two types of hormones:– Steroid hormones= can cross cell

membranes, enter the nucleus and turn cells on and off

– Nonsteroid hormones= cannot cross cell membranes

• All cells also produce hormonelike substances called prosaglandins that affect only NEARBY cells


• The endocrine system is regulated by feedback mechanisms that help maintain homeostasis

• Complementary Hormone Action= 2 hormones with opposite effects may work together to maintain homoestasis– EX: thyroid hormone and thyroid stimulating

hormone

Human Endocrine GlandsCh. 39-2

• Human endocrine glands include:– Pituitary Gland= controls actions of other endocrine

glands– Hpothalamus= Controls pituitary gland– Thyroid Gland= Regulates metabolism– Parathyroid Glands= Regulates calcium levels in

blood– Adrenal Glands= Produce hormones to help deal with

stress– Pancreas= Produces insulin to keep blood sugar

stable– Reproductive Glands= Produce gametes (egg &

sperm)

The Reproductive SystemCh. 39-3

• Sex hormones are produces by gonads of an embryo cause embryo to become either male or female

• Sex hormones cause puberty to occur between ages 9 – 15

• At end of puberty reproductive organs are fully developed and able to function


• The male reproductive system produces and delivers sperm

• Main organs of male reproductive system are:– Testes= produce sperm in tiny tubes called

seminiferous tubulues– Scrotum= hold testes– Vas Deferens= first tube sperm travel through– Urethra=Final tube that allows sperm to exit the body

from the penis


• The main function of the female reproductive system is to produce eggs and prepare the female body to nourish an embryo

• Main organs of the female reproductive system are:– Ovaries: Produce eggs– Follicles: cluster of cells found in ovaries that

surround egg and help it mature– Fallopian Tube: Egg travels through here where it can

be fertilized if sperm are present– Uterus: Final resting place of egg– Vagina: Connects uterus to the outside of the body


• One egg develops each months during the menstrual cycle that is controlled by hormones

• There are 4 phases to the menstrual cycle:– Follicular Phase= egg matures in the follicle and the

uterus is prepared to receive a fertilized egg– Luteal Phase= Follicle turns into structure called

corpus luteum – Fertilization= results in implantation in the uterus

• No fertilization results in menstration– Menstration= the lining of the uterus falls away and

exits the body through the vagina• Will not occur if the egg has been fertilized

Fertilization and DevelopmentCh. 39-4

• Fertilization is the process of a sperm joining an egg

• A fertilized egg is called a zygote• A week after fertilization, a blastocyst (hollow

ball the zygote becomes) implants itself in the lining of the uterus

• The blastocyst differentiates and becomes an embryo

• As the embryo develops, membranes also form to protect and nourish it and help remove waste– EX: Placenta forms and provides nutrients to the

fetus from the mother


• After 8 weeks of development the embryo is called a fetus

• By the end of 3 months, most of the major organs are formed

• The last 6 months are used for growth and maturation of fetal organs

• Childbirth results when hormones cause the mother’s uterus to contract

• Contractions push the baby from the mother’s uterus and out through the vagina


• Twins are born if more than one egg was fertilized (fraternal twins), or if the zygote splits into two embryos during early development (identical twins)

• Growth and development continue throughout infancy and childhood

• Adolescence begins with puberty and ends with adulthood

• The first signs of aging usually appear in the 30’s

Documents

The Human Body Part II Chapters 37-39. The Respiratory System Ch. 37-3 Respiration is the process by which oxygen & carbon dioxide are exchanged between