Transcript S7L2. Students will describe the structure and function of cells

The Human Body
7th Grade Life Science
Schley County Middle School
Coach Blocker
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Body Organization
Bodies must maintain homeostasis, a stable internal
environment, in order to survive
Cells form tissues, tissues form organs, organs form
organ systems, organ systems form the organism
Four Types of Body Tissue
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Epithelial – covers and protects under layers of tissue – stick
tightly together forming a continuous sheet
Nervous – sends electrical signals through body
Muscle – cells that can contract and relax to produce
movement
Connective – joins, supports, protects, insulates, nourishes,
and cushions organs
Skeletal System
Approximately 206 bones in
body
Functions
Protects internal organs (heart,
lungs, spinal cord, and brain)
Stores minerals for proper
functioning and fat for energy
(Calcium and phosphorus)
Anchors muscles to produce
movement
Makes blood cells in the marrow
Gives organisms body shape
and support
Skeletal System
Bones are organs with living tissue
Osteocytes – mature bone cells
Osteoblasts – deposit minerals in
bones (Build bone)
Osteoclasts – dissolve bone
(break down bone)
Compact bone – hard inner structure
Spongy bone – many open spaces –
provides most of the strength and
support
Marrow – soft tissue inside bones
 Red marrow produces red blood
cells
 Yellow marrow stores fat, and
produces white blood cells
Skeletal System
Bones begin as cartilage – soft flexible tissue and is replaced by
bone as you grow
Joint – place where 2 or more bones come together
1. Fixed (immoveable) joints
allow no movement – plates in skull
2. Moveable joints
have wide range of movement – these are more
susceptible to injury (4 types)
Ligaments – connect bones for movement
Strained ligaments heal – torn ligaments need surgery
Cartilage between bones wears away causing arthritis
Skeletal System
4 Types of Moveable Joints
Gliding or Sliding – allow hands, feet and back bones to glide over
one another
Ball and socket – allows movement in all directions – shoulder and
hip
Hinge – flex joint about 180 degrees – knees, elbows, fingers, toes
Pivot – allows rotation at a fix point – skull on spine
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Muscular System
Muscle is the major organ of the muscular system.
There are over 600 muscles in the human body.
The function of muscle is to create movement.
Three types of muscle tissue
 Smooth – digestive tract and blood vessels
 Cardiac – heart
 Skeletal – attached to bones for movement
Tendons – connect muscles to bones
Voluntary muscles – under your control – hand/arm/leg
movement
Involuntary muscles – not under control – heartbeat,
blinking, breathing
Muscular System
The brain sends electrical signals to muscles – muscles
respond by contracting or relaxing.
Muscles work in pairs – while one muscle is contracting
(shortening) another is relaxing (elongating).
Resistance exercises – most effective – overcome weight of
another object.
Hypertrophy – muscle increase in size
Atrophy – muscle decrease in size
Aerobic exercises – strengthens the heart and increases
endurance.
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Integumentary System
Major organs are skin, hair, and nails; Skin is the largest organ of the human body
Functions
1. Protection—forms a protective covering over the body that prevents injury
a. Many disease-causing organisms cannot pass through the skin.
b. Prevents excess water loss
2. Sensory response - nerve cells in the skin detect and relay information to the brain
3. Formation of vitamin D, which helps your body absorb calcium
4. Regulation of body temperature
a. Blood vessels in the skin help release or hold heat.
b. Perspiration from the sweat glands eliminates excess heat that has been
produced by muscle contractions.
5. Elimination of wastes through sweat glands
Integumentary System
Skin – made of three major layers
 Epidermis – thin outside layer
of skin – most cells are dead
epithelial tissue and contain
keratin which makes skin
tough
 Dermis – thick inside layer of
skin – connective tissue made
of collagen – provides strength
and the ability to bend without
tearing
 Subcutaneous Layer – fatty
layer
Integumentary System
Blood vessels – regulate body
temp
Nerves – carry messages to
and from brain
Muscle fiber – contracts the
hair causing it to stand up
Hair follicles – produce hair
Oil glands – release oil to
keep flexible – waterproofs
the epidermis
Sweat glands – cools skin
and removes waste
Integumentary System
Melanocytes – skin cells that produce melanin which
determines skin color – more melanin darker the skin –
absorbs harmful radiation
Hair follicle – new cells added to bottom and older cells
push upward
Hair protects from ultraviolet light, protects from dust and
insects, and help regulate body temperature
Nails protect tips of fingers and toes – form from base and
sides
Skin Cancer – uncontrolled cell division in skin
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Digestive System
Accessory organs (food does not pass through)
Teeth
Salivary glands
Liver
Pancreas
Gall bladder
Major organs (food passes through)
Mouth
Throat
Esophagus
Stomach
Small intestines
Large Intestines
Rectum and Anus
Digestive System
Major Functions:
Digestion of food
Absorption of
nutrients – Water,
protein, carbohydrates,
fats, vitamins, and
minerals
Elimination of waste
Digestive System
Two Types of Digestion
Mechanical Digestion –
crushing of food into smaller
molecules
Chemical Digestion –
molecules broken down into
nutrients

Enzymes – breaks down nutrients
into smaller particles
Digestive System
Teeth – break and grind food – made of
enamel
Salivary gland – makes saliva that begins
chemical digestion of carbohydrates –
saliva contains enzymes
Mouth – opening into the digestive
system – begins mechanical and chemical
digestion
Throat – back of the mouth where
peristalsis begins – epiglottis is the
protective cartilage that covers larynx as
food and liquids pass through esophagus.
Esophagus – transports food to stomach
using peristalsis – squeezing through with
muscle contractions.
Digestive System
Stomach – produces gastric juice – enzymes
and hydrochloric acid to kill bacteria and break
food down – converts food into chyme – a
soupy mixture
Small Intestine – connected to stomach –
mixes chyme with (bile) a green fluid from
liver and pancreatic juice – most chemical
digestion takes place here – and the absorption
of nutrients by diffusion
 Villi – fingerlike projections in small
intestines that contain nutrient-absorbing
cells – send nutrients to blood stream
 Bacteria in the small intestines help to clean
small intestines and digest fiber
Digestive System
Pancreas – makes pancreatic juice containing
bicarbonates that neutralized the acid in chyme –
also makes hormones to regulate blood sugar
Liver – makes bile to digest large fat molecules–
stores nutrients – breaks down toxic substances –
makes cholesterol
Gallbladder – stores bile from liver and transports
it to the small intestine
Large Intestine – processes material that was not
absorbed in small intestine – reabsorbs most water
and compacts solid mass called feces or stool –
bacteria live in large intestines and process
vitamins
Rectum stores feces till it passes out the anus
Digestive System
Problems That May Occur in the Digestive System
Heartburn – sphincters (muscles) block off stomach from
backflow of stomach acid – when it does backflow it
causes the burning pain in chest
Constipation – when bowel movements become difficult
and infrequent due to lack of water/fiber in stool
Diarrhea – when bowel movements are frequent and
water is not removed from stool
Colon Cancer – uncontrolled cell division in colon
Gastric Ulcer - an open sore in the stomach lining
Essay
Describe, step by step, what
happens to an apple, from
first bite to end products, as it
is digested in the body. Use
proper vocabulary!
Warm-Up
In the mouth, the tongue and teeth begin mechanical digestion to break
the apple down into smaller particles. Saliva, which contains the enzyme
amylase, begins chemical digestion, breaking down starch into sugar.
Then, through peristalsis, the esophagus moves the apple particles into the
stomach. In the stomach, food is mixed mechanically by peristalsis. It is
also broken down by acids with the help of enzymes and changed into
chyme. The chyme flows into the small intestine, where it is further
digested chemically, as bile and pancreatic juice are mixed with the
chyme. Nutrients are absorbed by the villi in the small intestines into
blood vessels, and then transported to all the cells of the body. The
remaining undigested materials move into the large intestine, where water
is absorbed from it, and it becomes more solid. Finally, the rectum and
anus control the release of the remaining solid wastes.
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Cardiovascular System
(Circulatory System)
Major organs – heart,
blood, and blood vessels
Functions
Transports oxygenated
blood and nutrients to the
cells and takes away
waste from the cells.
Transports waste
materials away from cells
Cardiovascular System
(Circulatory System)
Blood vessels - hollow tubes
that transport blood
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Arteries – take blood away
from the heart – they have
thick walls to handle the
pressure and this is where you
feel your pulse
Capillaries – allows material
to diffuse through the wall to
cells and back
Veins – take blood back to
heart
Cardiovascular System
(Circulatory System)
Blood – connective tissue that
is made of red blood cells,
white blood cells, and platelets
that float in plasma – the
liquid part of blood
Red blood cells supply oxygen
 RBC’s contain hemoglobin
– protein that clings to
oxygen
RBC’s are made in the red
bone marrow and replaced
every 4 months
Cardiovascular System
(Circulatory System)
White blood cells (WBC) –
destroy pathogens
WBC’s surround the pathogen
and destroy it or they release
antibodies – chemicals that
destroy them.
WBC’s made in yellow bone
marrow and in lymphatic organs
Platelets – clot blood by
clumping together in damaged
area to prevent blood loss – made
in bone marrow and only live 510 days
Cardiovascular System
(Circulatory System)
The heart pumps blood to
the lungs then through the
body
Heart has 4 chambers
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Upper chambers are called
atria (atrium singular)
Lower chambers are called
ventricles
The right and left side of
the heart are separated by
the septum
Cardiovascular System
(Circulatory System)
Three Types of Circulation
Pulmonary circulation –
when blood is transported from
the heart to the lungs, then back
to the heart
Systemic Circulation – when
blood is transported from the
heart to the rest of the body
Coronary Circulation – blood
transported throughout the
heart itself
Cardiovascular System
(Circulatory System)
Blood pressure – is the force exerted by blood on the blood
vessel
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Systolic pressure – first number – pressure in arteries when ventricles
contract
Diastolic pressure – second number – pressure in arteries when ventricles
relax
4 blood types
 Type A – A antigens
 Type B – B antigens
 Type AB has both antigens – can get any type of blood –
universal recipient
 Type O has neither antigen – can be given to anyone –
universal donor
Cardiovascular System
(Circulatory System)
Disorders of the Circulatory System
Atherosclerosis – when cholesterol builds up
inside blood vessels – become narrower and
less elastic – causes heart attacks
Hypertension – abnormally high blood
pressure
Stroke - when blood vessels in the brain
become clogged or rupture
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Lymphatic System
Collects excess fluids and returns
them to the blood stream and
fights pathogens
Lymph capillaries – absorb fluid
and particles too large for
capillaries
Lymphatic vessels – larger
vessels with valves to prevent
backflow
Lymph – fluid and particles
absorbed by the lymph capillaries
Lymphatic System
Lymph Nodes – small bean-shaped
organs where particles are removed from
lymph
Thymus – located just above heart –
releases WBC’s to travel to other areas
Spleen – largest lymph organ – upper left
side of abdomen – filters blood and
releases WBC’s
Tonsils – located in back of nasal cavity
and back of tongue defend against
infection
Diseases include – swelling of lymph
nodes, Lymphomas – cancer of the
lymphatic system, enlarged spleen and
tonsillitis.
Causes of Diseases
Noninfectious Diseases – can’t be spread
from one person to another – cancer, heart
disease etc.
Infectious Diseases – can be passed from
one person to another – cold, flu etc.
Pathogens – bacteria or viruses that cause
diseases
Causes of Diseases
How are they passed?
Through the air – sneezing, coughing
 Contaminated objects – things sick people
touch
 Person to person contact – when you touch a
person with the disease
 Animals – that bite or sting
 Food and water – contains pathogens
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Defending Against Diseases
How do we counter these problems?
Pasteurization – heating milk to kill bacteria
 Vaccines – shots containing dead
bacteria/viruses so the body can identify them
when live ones enter the body
 Antibiotics – kill pathogenic bacteria

Defending Against Diseases
Macrophage – engulf and eat pathogens
T-Cells – coordinate the immune system
B-Cells – make antibodies
Antibodies – attach to the pathogen and
help with the destruction
Defending Against Diseases
Steps to kill pathogens
Macrophage shows pieces of pathogens to other
cells
 Antigens who have seen the pathogen activate
the T-Cells
 T-Cells divide to create Helper T-cells
 Helper T-cells find a killer T-cell – the Killer
T-cells start to identify and kill infected cells

Defending Against Diseases
Helper T-Cells now activate B-Cells
 B-Cells make antibodies that cling to the
pathogen and act as markers. When the
markers are seen, immune cells and proteins
swarm and attack the pathogen
 Proteins and immune cells enter the pathogen
and kill it
 Macrophages then engulf the pathogens that
were tagged and killed

S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Respiratory System
Respiration is the
entire process by
which a body obtains
and uses oxygen and
gets rid of carbon
dioxide and water.
Oxygen is needed to
convert food to
energy.
Respiratory System
Parts of the respiratory system
 Nose – primary passage in and out
 Pharynx – air, food, and drink pass
through this – splits into two tubes –
one to lungs and one to stomach
 Larynx – voice box – controls vocal
cords which vibrate to produce
sound
 Trachea – windpipe from larynx to
lungs
 Bronchi – 2 pipes – one leads to
each lung bronchioles – tiny tubes
 Lungs – contain air – forms tiny air
sacs called alveoli – capillaries get
oxygen from alveoli
 Diaphragm – muscle that makes
you breathe
 Alveoli – tiny sacks that hold air
Respiratory System
Disorders of the respiratory
system
Asthma – bronchioles constrict
and secrete mucus
Bronchitis – irritation to lining
of bronchioles
Pneumonia – bacteria or virus
inside lungs
Emphysema – eroded lung
tissue due to smoking
Lung cancer – growth of extra
tissue due to smoking
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Excretory Systems
Excretion is the process by which
waste products of metabolism
and other non-useful materials
are eliminated from an
organism.
Four Systems of Excretion
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Skin – releases waste in sweat
Digestive system – release feces
from the body
Lungs – expel carbon dioxide and
water
Urinary system – removes waste
Urinary System
Purpose is to excrete waste –
removing wastes and excess
products from the body
Kidneys – bean shaped – filters
harmful substances from the
blood

Nephrons – microscopic filters
that remove the waste from blood
Ureter – carries urine from each
kidney to the bladder
Bladder – holds urine for the
body
Urethra – carries urine to the
outside of body
Urinary System
Antidiuretic Hormones –
hormone that tells kidneys
to take back water from
nephrons and return to
bloodstream – making less
urine.

Hormones – chemicals that
control actions somewhere
else in the body
Diuretic Foods – caffeine
is one type that makes
more urine
Urinary System
Bacterial Infections – very
painful and needs to be treated
to prevent death of kidneys
Kidney stones – salt and waste
collects inside kidneys and
forms small mass which is
painful to release
Kidney disease – when kidneys
don’t function properly and
blood is filtered through a
machine
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Nervous System
A complex network of nerves and cells
that carry messages to and from the brain
and spinal cord to various parts of the
body.
Neuron Structure
 Cell body – contains nucleus and
organelles
 Dendrites – branched extensions that
receives messages
 Axon – fiber that transports
information
 Axon terminal – tip of axon that
connects to dendrite
Nervous System
Three types of Neurons
Sensory – gathers info and sends to central
nervous system; smell, taste, touch, vision, and
hearing
 Motor neurons – receive impulses from brain
or spinal cord to cause muscles to react
 Interneurons – interpret and relay information
from sensory neurons to motor neurons; found
in brain and spinal cord

Nervous System
Two Main Divisions
Central Nervous System –
brain and spinal cord
Peripheral Nervous System
– consists of the nerves other
than the brain and spinal cord.
Nervous System
Central Nervous System
 Brain – largest organ in system –
controls voluntary and involuntary
actions – contains 3 parts
 Cerebrum – largest part –
dome shaped part where you
think and where most memories
are stored – controls voluntary
movement
 Cerebellum – second largest
part – receives sensory impulses
from muscles and joints – keeps
track of body position
 Medulla – connects brain to
spinal cord – controls
involuntary actions
Nervous System
Spinal Cord - contains neurons and
axon bundles from the brain –
surrounded by vertebrae for protection.
Enables brain to communicate with
peripheral nervous system
Injury to spinal cord causes paralysis –
inability to send messages to lower
body
Reflex actions – a quick involuntary
action to prevent injury to a body part
Responding to the Environment
Sensations – when electrical signals
are sent to the brain for interpretation
Types of sensations
 Vision – awareness of light
energy
 Eye contains
 Pupil – adjusts light
 Retina – light sensitive layer
in back of eye
 Rods – dim light
 Cones – sees color
 Iris – color part of eye
 Lens – changes direction of
light in eye to adjust focus
Responding to the Environment
To hear, object vibrates which
pushes on the surrounding air until
it reaches the ear
Parts of the ear
 Outer ear – part you see –
funnels sound
 Middle ear – eardrum moves
tiny bones
 Hammer, anvil, stirrup
 Cochlea – snail shaped
bone that converts waves to
electrical impulses
 Inner ear – sends impulses to
brain
Responding to the Environment
Taste is the awareness of
certain dissolved chemicals
Taste buds – receptors for
taste
Papillae – tiny bumps on
tongue that contain taste
buds
Taste is closely related to
smell
Olfactory cells – in upper
nasal passage, react to
chemicals inhaled
Responding to the Environment
The nose has two holes called
nostrils. The nostrils and the nasal
passages are separated by a wall
called the septum
Closer to the tip of your nose, the
septum is made of cartilage which is
flexible material that's firmer than
skin or muscle.
Behind your nose, in the middle of
your face, is a space called the nasal
cavity. It connects with the back of
the throat. The nasal cavity is
separated from the inside of your
mouth by the palate (roof of your
mouth).
Responding to the Environment
Your nose is more than a passageway for air. The nose
also warms, moistens, and filters the air before it goes to
the lungs.
The mucus membrane (mucus and hairs in your nose)
captures dust, germs, and other small particles that could
irritate your lungs.
Up on the roof of the nasal cavity (the space behind your
nose) is the olfactory epithelium which contains special
receptors that are sensitive to odor molecules that travel
through the air.
Responding to the Environment
There are hundreds of
different odor receptors,
each with the ability to
sense certain odor
molecules.
When the smell receptors
are stimulated, signals travel
along the olfactory nerve to
the olfactory bulb. This send
the information brain to be
interpreted as a smell you
may recognize.
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Endocrine System
Controls long-term processes – fluid balance,
growth, and sexual development
Major organs
Glands – groups of cells that make hormones

Hormones – chemicals that control actions somewhere
else in the body
 Epinephrine or adrenalin – speed up heartbeat and
breathing
Endocrine System
Pituitary gland – secrets hormones
that affect other glands
Adrenal gland – responds to stress
and danger
Pancreas – regulates blood sugar by
producing insulin
Thyroid – increases the rate at
which you use energy
Parathyroid – regulates calcium
Thymus – regulates immune system
Ovaries – females – produces
estrogen
Testes – males – produces
testosterone
S7L2. Students will describe the structure
and function of cells, tissues, organs, and
organ systems.
e. Explain the purpose of the major
organ systems in the human body (i.e.,
digestion, respiration, reproduction,
circulation, excretion, movement,
control, and coordination, and for
protection from disease).
Reproductive System
Produces gametes used in fertilization

Sexual Reproduction requires two parents
Male Reproductive system

Testes – produces the male gamete (sex cell)
called sperm.
Female Reproductive System

Ovaries – produces the female gamete called
the egg/ovum.
Male Reproductive System
Female Reproductive System
Reproductive System
Fertilization – ovum (haploid) and sperm
(haploid) fuse together to create a new
diploid cell called the zygote.
Pregnancy - the zygote begins many cycles
of mitosis, and the zygote implants in the
female uterus.
As many new cells are created from this
zygote, the growing number of cells begin
to specialize to from an embryo.
Reproductive System
Embryo
Fetus
New Born
Human Life Stages
Fertilization – zygote forms
Embryo – fertilized egg that has attached to the wall of the
uterus
Fetus – developing baby after the first two month of pregnancy
Birth – baby emerges from mother
Infancy – (first 18 months) period of rapid learning and growth
Childhood – after infancy to age 12 or sexual maturity
Adolescence – age 12 to age 18; final growth spurt occurs
Adulthood – growth of skeletal and muscular systems stops
Older Adulthood – over the age of 60; decline of body
systems
Death – physical life ceases