The Skeletal and Muscular Systems

1. Provide the body with shape and support

2. Allow for motion

3. Produce red blood cells

4. Produce immune response cells

Skeletons and Muscles In Other Animals

• Animals tend to be divided into those with skeletons and those without (jellies, sea anemones, etc.).

• The ones with skeletons are divided into external (insects, crabs, clams, etc.) and internal (amphibians, reptiles, birds, and mammals).

• External skeletons must be shed as the animal grows.

• Starfish use a water pressure system for movement.

Bone Structure and Function• Bones are made of calcium rich cells

called osteocytes, which surround tiny canals that carry nutrients to the cells.

• Within this system of cells and canals, in the long bones of the leg, are hundreds of thousands of small spaces where red marrow can be found. It is in this marrow that red blood cells and B and T cells (immune system) are made.

Bone Structure and Function

Joints

1. Fixed—the skull is an example

2. Ball and Socket—rotates in all directions—shoulder and hip are examples

3. Hinge—creates a back and forth motion—knees and elbows are examples.

Muscle Structure and Function• Muscle is a long thread like tissue compose

of thin fibers tightly compacted. • These fibers are made of two proteins called

actin and myosin.

• These fibers slide past one another when muscles contract.

Muscle Structure and Function continued…

• A nerve response causes calcium ions to flow, which causes the actin to contract, or come together around the myosin fibers.

• This response causes the entire muscle to contract.

Muscle Types1. Skeletal—voluntary movement of

striated muscle. Allows for body movement.

2. Smooth—involuntary movement—movement of internal organs.

3. Cardiac—striated but involuntary—heart muscle.

Muscles of Human Body

Tissues Necessary for Movement1. Bone—gives body structure and support

2. Muscle—specialized tissue that contracts to give bones movement.

3. Cartilage—lines joints and gives protection.

4. Ligaments— tissue surrounds bone and holds it together.

5. Tendons—tissue connecting muscle to bone.

Muscle—Bone Interaction

• Muscles are attached to bones by tendons.

• Muscles work in pairs. One extends while its opposite flexes.

• Flexing is contracting, or pulling the muscle together.

• Extending is relaxing the muscle which allows it to stretch out.

Muscle and Bone Facts• Cartilage, ligaments, and tendons do not contain

blood vessels, and therefore can not repair themselves.

• Muscle and bone can repair themselves if torn or broken.

• Muscles always pull, they never push.

• 80% of our body weight is bone.

• The average person makes 2,000,000 red blood cells in bone marrow per second.

• The femur is the largest bone.

• The inner ear is the smallest bone.

Immune System Function

• The function of the immune system is to identify and destroy disease causing bacteria and other foreign substances (called pathogens).

Immune Systems in Other Animals

• Bacteria fight invaders by simply mutating. They are so simple that mutations occur regularly and have profound effects.

• Sharks seem to be immune to cancer, for reasons we have not yet figured out.

How the Immune System Works

• White blood cells (called pathogens) identify foreign proteins called antigens.

• Antibodies (proteins that attach to antigens) match up to antigens and attach to them.

• This allows macrophages (cell eating molecules) to consume the antigens.

Attack Lymphocytes

1. B Cells-cells produced by red bone marrow that attack antigens. They contain the antibody proteins on their outer cell membrane.

2. T Cells—cells also produced in red bone marrow. They also attach to antigens and help destroy it.

3. Suppressor T Cells—specialized T cells that regulate how strong the immune response is.

4. Cytotoxic T cells—specialized T cells that are specific to destroying cancer cells.

Macrophages and Lymph

• Macrophages—specialized white blood cells that destroy antigens.• They are stored in lymph glands.

• Lymph is the fluid that contains macrophages. • It flows through the body and past lymph

nodes where antigens are collected and destroyed.

Protect Yourself! First Lines of Defense

1. Skin—prevents most bacteria and viruses from entering the body.

2. Hair—traps bacteria in the nose.

3. Acidic chemicals in mucus from the nose, saliva from the mouth, and tears from the eyes.

Second Lines of Defense

1. Histamines—chemicals released when something foreign enters the body. They increase blood flow, which brings more white blood cells to the area of invasion.

2. White Cells (lymphocytes)—they engulf the invaders and destroy them.

3. Temperature—A rise in body temperature helps destroy foreign substances as well.

Immune System Facts• There is a specific antibody created for every antigen

(foreign invader).

• When lymphocytes attack an antigen, they create memory cells which recognize the invading bacteria. If the same invader enters your body again, the response is immediate. Therefore, you can’t get sick from the same bacteria twice.

• The spleen holds blood, filters out and destroys dead red blood cells, and helps B cells make antigens.

• AIDS is a virus that attacks the immune response by preventing T and B cells from destroying antigens.

Circulatory System Function

• To transport oxygen and nutrients to body cells, and to remove carbon dioxide and waste molecules.

Circulation In Other Animals

• Simple animals like insects and spiders have open circulatory systems in which the nutrients and waste simply flow throughout the body.

• Fish have a two-chambered heart (oxygenated and deoxygenated blood mixes) , while amphibian’ heart is three-chambered.

• Humans have a four-chambered heart which allows for complete separation of oxygenated and deoxygenated blood.

Blood• The human body contains 5 to 6 liters

of blood (or 7-8% of body weight.)

• Each blood cell lives approximately 4 months.

• Blood contains red cells (carry oxygen), white cells (fight foreign substances), platelets (for clotting), and plasma (55%) (basically water, proteins and minerals).

Blood Vessels1. Arteries—thick walled, they carry

blood away from the heart.

2. Veins—thin walled, they carry blood toward the heart.

3. Capillaries—very thin and microscopic in size, they allow blood cells single file to exchange gases and nutrients with cells around the body.

The Heart

• The heart is a hollow muscle that contracts at regular intervals to pump blood throughout the body.

• It has four chambers separated from each other by valves that open and close in one direction only. This way, oxygen rich blood never mixes with deoxygenated blood.

The Mammal and Bird Heart

The Complex Human Heart

Blood Pressure• Blood Pressure is what is created

when the heart contracts and forces blood through the arteries to the body.

• Normal pressure is 120/80.

• High blood pressure can be a result of the narrowing and hardening of blood vessels as one ages.

Circulatory Facts1. The heart is approximately the size of a fist.

2. It pumps 2,000 gallons of blood per day.

3. It takes 20 seconds for one blood cell to completely circulate through the body.

4. There are 8 million blood cells being produced every minute.

5. The heart beats 3 billion times in an average lifetime.

Respiratory System Function

• To get oxygen to all the cells of the body and to remove carbon dioxide from all of the cells in the body.

Respiration In Other Animals

• Simple animals like spiders and insects have modified gill or trachea system that allows for gas exchange.

• Marine animals such as shrimp and lobster, along with fish have gills (smaller surface area).

• Amphibians have gills to begin life and then lungs as adults.

• Reptiles, birds, and mammals all have lungs.

Nose, Mouth, and Nasal Cavity

• Air, containing oxygen, enters the nose or mouth and is moistened.

• Moisture is present because oxygen and carbon dioxide dissolve in water.

• Nasal hairs filter out foreign substances.

Pharynx and Larynx

• The pharynx is the opening to the digestive system. • Sound is created (voice box).

• Long, stringy tissue vibrates when we talk, producing sound.

• The larynx is opening to the lungs.

• The epiglottis covers the larynx when food is swallowed.

Trachea

• The trachea is the passageway to the lungs. • It is made of rings of cartilage.

• These rings keep the trachea from collapsing or expanding when the body moves.

• It is lined with tiny hairs that filter out foreign substances.

Bronchi

• The trachea branches into two small tubes that lead to lungs. • These tubes are called the bronchi.

• Air passes through the bronchi into the lungs.

Lungs and Alveoli

• The lungs are to sack-like structures at the ends of the bronchi.

• They contain thousands of small air sacs called alveoli.

• These small air sacs create a large surface area so that more gases can be absorbed and released.

• Capillaries attach to each alveoli.

• Oxygen is taken into the blood and carbon dioxide is released.

Respiratory System

The Diaphragm

• The diaphragm is a large flat muscle under the lungs that separates the chest from the abdominal cavity.

• When this muscle contracts. It is pulled down. This lowers the pressure and causes the lungs to expand and fill with oxygenated air.

• The diaphragm then relaxes and pushes up, This raises the pressure and forces deoxygenated air out of the lungs.

• This process goes on 10 to 18 times per minute.

Breathing

The Control of Breathing

• Breathing is controlled by the amount of carbon dioxide in the blood.

• Carbon dioxide breaks down to form carbonic acid in the blood.

• When the nerves connected the blood vessels detect a certain acid level, then the brain sends a signal to the diaphragm to breathe.

Respiratory Facts

1. Five liters of blood filter through the lungs every minute.

2. Eight liters of air through the lungs per minute.

3. The surface area of the lungs equals the size of a tennis court.

Digestive System

• The purpose of the digestive system is to breakdown food into simpler molecules (glucose, fats and proteins) that can be absorbed into blood and used by the cells.

Digestion In Other Animals

• Simple animals like jellies have a two way digestive system (food comes in and food goes out the same opening.

• More complex animals have a one-way digestive system (food goes in one opening and out another—it flows only one direction).

• Some animals filter food particles from the water (tube worms) and some simply absorb it into their bodies (flat worms).

Mouth and Salivary Glands

• Food is broken down by chewing in the mouth.

• The salivary glands then begin to digest the food.

• The salivary glands also produce moisture.

• The tongue has taste buds.

Pharynx and Esophagus

• The pharynx is the passageway for food to the esophagus.

• The esophagus is the passageway to the stomach. It passes the heart, between the lungs, and through the chest to the abdomen. • It is surrounded by circular muscles that contract

in rhythm to push food down to the stomach.

• Peristalsis

The Stomach• The stomach is where the major breakdown of

food occurs.

• Pepsin (breakdown of protein), mucus (lubrication), hydrochloric acid (carbohydrate breakdown), lipase and bile (fat breakdown) are chemicals produced by the liver and pancreas.

• These chemicals break the food down so it my pass to large intestine.

• pH of 1.5

Liver and Pancreas• Liver--the largest gland in the body. It

produces bile (a chemical that breaks down fats) and filters out old red blood cells. The bile is produced and then stored in the gall bladder until needed.

• Pancreas--produces lipase and other enzymes. It produces insulin for carrying glucose into the blood. It also makes sodium bicarbonate to return the digestive juices pH to 8.0.

Small Intestine• The digested food passes into the small intestines from the

stomach.

• In the upper small intestine more sugar and fat breakdown occur.

• When the food passes into the lower small intestine more protein and sugar breakdown occur.

• The small intestines are between 20 and 25 feet in length.

• The broken down sugars, fats, and proteins are absorbed into capillaries surrounding the small intestine.

• They are then carried throughout the body.

Large Intestine

• Remaining undigested food, water, and cellulose (fiber) pass from the small intestine into the large intestine (6 feet long).

• Water is picked up by capillaries and taken where needed in the body, by the blood.

• The unused solid material (feces) then passes the appendix (function unknown) and out of the body through the rectum and anus.

Digestion Facts

• Helpful bacteria live in the mouth, stomach, and colon (large intestine).• They keep fungus from growing, aid in

digestion, and help make important vitamins.

• The average person eats 50 tons (100,000 pounds) of food in a lifetime.

The Excretory System

• The function of the excretory system is to remove waste and return useful materials to the body.

• To maintain the water balance in the body.

Excretion In Other Animals

• Earthworms have tiny tubes in each body segment that exchange oxygen and carbon dioxide with the air.

• Grasshoppers have tiny tube structures in their intestines for the same purpose.

• Amphibians, reptiles, and birds solid and liquid waste is mixed together.

• Mammals have separate organs for liquid and for solid waste.

Kidneys and Bladder

• The kidneys remove waste and excess salts from the blood.

• Blood flows through the nephrons that are surrounded by capillaries.

• The waste materials flow out of blood and into the kidneys, along with excess water.

• This is called urine (urea, water, salts).

• The urine is stored in the bladder and then leaves the body through the urethra.

Others Organs Involved with Waste1. Lungs expel carbon dioxide and water

droplets

2. Skin releases water, urea, and salts with help from sweat glands.

3. Liver filters out excess amino acids and dead red blood cells.

4. Large Intestine excretes salts, bile, and undigested solid food matter.

Human Excretory System

Excretory Facts1. Blood passes through the kidneys 300 times a

day.

2. Dialysis is an artificial way of filtering blood when the kidneys no longer work efficiently.

3. All of your blood is cleaned in 45 minutes.

4. Urine is 70 times more concentrated in salts. Water. And waste than blood.

The Nervous System

• The nervous system controls all body functions and movements. It interprets stimuli from the outside world.

• Neurons in the brain

Nervous Systems In Other Animals

• Simple animals like insects and spiders have a few nerve cells clumped together called ganglia that help control body functions.

• Fish, amphibians, and reptiles have small, simple brains, similar to the human cerebellum that controls body functions. They have significantly fewer nerve endings, so feel pain much less than humans.

• Mammals have more complex, and larger brains, but only humans have developed language skills and the ability to reason.

Human Nervous System

• The brain (approximately 3 lbs.) controls movement, maintains homeostasis, and controls reasoning and problem solving.

• Spinal chord is the major pathway for nervous impulses throughout the body.

• Nerves are the pathways that carry the nervous impulses to and from the brain and body organs.

The Brain

• The brain is divided into three parts

• Cerebellum - controls balance and movement

• Cerebrum - reasoning, language, and problem-solving

• Medulla or brain stem - controls involuntary movements like breathing and heart beat

Other Parts of the Brain

• The brain also contains smaller areas:

• thalamus - a relay station for incoming impulses

• hypothalamus - regulates homeostasis

• pituitary - a gland that makes growth hormones and other chemicals

The Brain

Brain Function

• The frontal lobe of the brain is where thinking and reasoning take place.

• The temporal lobes (sides of brain) control hearing and speech.

• The occipital lobe is in the rear of the brain and controls vision.

• The parietal lobe is on top of the brain and controls sensations like taste and touch.

Brain Function

Brain Function continued…

• Senses enter our brain and must first pass through the amygdala.

• This is a small area deep inside the middle of the brain that controls emotions.

• Because almost all sensations pass through this juncture before they are stored, most of our memories have emotional attachments to them.

The Power of Smell

• The sense of smell is the strongest sense because it has a direct path to the cerebrum, as where the other senses must pass through relay stations first.

Nerves

• There are two types of nerves; somatic, which control muscle movement and autonomic, which control internal organ functions.

• Nerves are made of neurons. • Sensory neurons carry messages from ears, eyes,

nose, etc. to the brain.

• Motor neurons carry messages to the muscles to react to the incoming stimuli.

How a Neuron Works1. Neurons are composed of an axon (carries messages away from

the cell to the next cell, a dendrite (carries messages to the cell) and a synapse (the “bridge” between axons and dendrites).

2. Schwann cells are scattered between nerve cells to provide nutrients to the nerve cells.

3. Sodium ions build up outside of the nerve cell, while potassium ions build up inside of the cell. This is accomplished by active transport in the cells.

4. When the nerve “fires” sodium ions flow into the cell and potassium ions flow out. This flow of ions causes the nerve to fire and send the necessary information to the brain or from the brain to the muscles.

5. A chemical called acetylcholine and the myelin sheath in the nerve cell allows this process to occur very rapidly.

Nervous System Facts

1. 20% of a persons daily calories go to brain functions.

2. The brain works better when the body has plenty of water and glucose.

3. New information gets stored best when the person talks.

4. The brain can only store approximately eight new words, ideas, etc. at a time.

The Endocrine System

• The function of the endocrine system is to regulate growth, metabolism, and reproduction by producing and distributing hormones (chemical that, in small amounts, regulate body activities).

Endocrine Systems In Other Animals

• In general, only animals with well developed nervous and circulatory systems have endocrine systems composed of glands that produce hormones.

• Humans have over 50 different hormones being produced.

Brain Glands

• Thyroid gland—small gland in the neck that produces thyroxin (controls the rate of metabolism).

• Parathyroid—four small glands behind the thyroid gland that regulate salt (calcium and potassium) production. Too little can create muscle spasms and convulsions. Too much can cause tumors.

• Pituitary—A very small gland in the skull that produces growth hormone, hormones that control ovary and testes growth, and milk production in pregnant women.

Glands in the Chest

• Thymus—Stores and stimulates the growth of lymphocytes.

• Pancreas—considered part of digestive system it produces insulin.

• Adrenal Glands—on top of kidneys—produces sex hormones and adrenaline (secreted in emergencies it increases heart rate and respiration.

Sex Glands

• Ovaries in women produce estrogen which controls mammary gland development, menstruation, and mood changes.

• Testes in men produces progesterone which stimulates growth of facial hair, large larynx (Adam’s apple), and muscle development.

Endocrine System

Endocrine Facts

1. The pineal gland secretes melatonin which helps control sleep. It is affected by light.

2. It takes two hours of wakefulness (and light) to clear the system of melatonin.

Reproductive System

• To create more individuals of the species.

• To assure healthy offspring by creating variation in DNA, due to separate sexes.

Reproduction In Other Animals• Simple organisms like hydra and starfish can

simply divide (asexual) and develop whole new organisms.

• This is easier than finding a mate, mating, etc.

• However, it does not provide variety of DNA, which can be deadly to a population if the environment changes rapidly.

• Most animals have sexual reproduction, which requires both male and female members.

Reproduction In Other Animals continued…

• External Fertilization occurs in many less complex species. Water must be present. Higher risk of eggs being eaten and of fertilization occurring successfully. Must have many offspring.

• Internal Fertilization More successful and better protection for young. Must have separate sexes (with the exception of hermaphrodites). Can have fewer young safely.

Female Reproduction• Women are born with all of the eggs they will ever have.

• The eggs remain in prophase I of meiosis in their ovaries until hormones begin to be released on a monthly cycle.

• After the hormone production begins (puberty) one egg is released each month.

• The egg travels to the uterus, through the oviduct and fallopian tube, and if fertilized attaches itself to the uterine lining.

• The ovaries alternate in releasing eggs.

• The uterine lining fills with nutrient rich blood throughout the monthly cycle.

• When the fertilized egg attaches itself it will have nourishment to begin development.

• If no egg attaches (no fertilization) then the lining is shed and the blood passes out of the body through the vagina.

Female Reproduction

Male Reproductive System

• Sperm is produced in the testis, outside of the body; normal body temperature is too high for sperm to live.

• The sperm leave the testis and join with a fluid produced in the prostate gland that allows them to “swim”.

• Together the sperm and fluid are called semen.

Embryo Development

• Once an egg has attached itself to the lining of the uterus, it begins to divide (called cleavage) and grow.

• It feeds on fat and protein in the lining.

• The umbilical cord feeds the developing fetus until birth (approximately 9 months).

Reproduction Facts• The average male produces

200,000,000 sperm per day.

• The average female is born with 500 eggs.