Transcript Human Body II Ch. 35-39

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 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
Ch. 37-3
• 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
The Respiratory System
Ch. 37-3
• 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.
The Respiratory System
Ch. 37-3
• 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 Nutrition
Ch. 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
Food and Nutrition
Ch. 38-1
• 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
Food and Nutrition
Ch. 38-1
• Vitamins are organic molecules that help
regulate the body
• Minerals are inorganic molecules that
perform vital functions in the body
– EX: Calcium & iron
Food and Nutrition
Ch. 38-1
• 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
Food and Nutrition
Ch. 38-1
• 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 and Nutrition
Ch. 38-1
• 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)
Food and Nutrition
Ch. 38-1
• 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
Food and Nutrition
Ch. 38-1
• 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 System
Ch. 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
The Excretory System
Ch. 38-3
• 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
The Excretory System
Ch. 38-3
• 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 System
Ch. 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
The Endocrine System
Ch. 39-1
• 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
Ch. 39-1
• 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 Glands
Ch. 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 System
Ch. 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 Reproductive System
Ch. 39-3
• 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 Reproductive System
Ch. 39-3
• 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
The Reproductive System
Ch. 39-3
• 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 Development
Ch. 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
Fertilization and Development
Ch. 39-4
• 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
Fertilization and Development
Ch. 39-4
• 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