The Human Body Systems

Chapters 35-40

Organization of the Body

• The level of organization in multicellular organisms include: Cells Tissues Organs Organ Systems.

• Humans have 11 organ systems– Functions of Organ Systems: Maintains

homeostasis in the body as a whole.

Organization of the Body• Cells

– The Basic Unit of Structure– Specialized structures: uniquely suited to perform a

particular function• Tissues – a group of cells that perform a single

function– Four Basic Types:

• Epithelial Tissue: Cover the interior and exterior of body surfaces

• Connective Tissue: Connects and Supports • Nervous Tissue: Transmits nerve impulses• Muscle Tissue: Enable the body to move

Organization of the Body

• Organs – Group of tissues that work together to perform a single function

• Organ systems – groups of organs that perform closely related functions.– Humans have 11 organ systems

• Functions of Organ Systems: Maintains homeostasis in the body as a whole.

Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Human Organ Systems

Respiratory System Digestive System Excretory System

Endocrine System Reproductive System Lymphatic/Immune Systems

Human Organ Systems

Maintaining Homeostasis• Homeostasis: The process which

organisms keep internal conditions relatively constant despite changes in external environment– Feedback inhibition: The process in which a

stimulus produces a response that opposes the original stimulus

Negative Feedback

The Skeletal System

• Skeletons provide support for an organisms and the skeletal system is composed of bones and connective tissue (called cartilage and ligaments).

• The Skeleton– Functions of the skeleton:– Supports the Body– Protects internal organs– Allows Movement– Stores Minerals– Site for blood cell formation

• Adult human skeleton had 206 bones

The Structure of Bones

• Bones are a solid network of living cells and protein fibers that are surrounded by calcium deposits.

• Types of Bone cells:– Osteocytes - mature bone cells– Osteoclasts - break down bone– Osteoblasts - produce bone

Development of Bones

• Skeleton of an embryo is made up of cartilage.

• Ossification: The process of replacing cartilage with bone – Begins about 7 months before birth.

Types of Joints

• Joint: The place where one bone attaches to another.

• Ligaments: Hold bones together in a joint• Three Types:

– Immovable Joints• Allow no Movement/bones are interlocked

– Skull

– Slightly Moveable Joints:• Allow small amount of Movement• Bones separated from each other

– Two bones of lower leg meet.

Types of Joints

• Freely movable Joints:– Permit movement in one or more directions– Most Common Types:

• Ball-and-socket: Movement in many directions

• Hinge: Back and Forth motion

• Pivot: One Bone rotates around another

• Saddle: One bone to slide in two directions

Types of Joints

The Muscular Tissue

• This system is required for bones to move.

• Three types of Muscle Tissue:– Skeletal– Smooth– Cardiac

Types of Muscle Tissue

• Skeletal Muscle:– Attached to bones– Responsible for Voluntary Movement– Striated– Consciously Controlled– Large with many nuclei/long and slender

often called muscle fibers.

Types of Muscle Tissue

• Smooth Muscle– Not under voluntary control– One nucleus and not striated– Found in Stomach, intestines, and blood

vessels– Can function without nerves stimulation

Types of muscles

• Cardiac Muscle– Found only in the heart– Small Cells, Striated– One or two nuclei– Not under direct control of the Brain.

Types of Muscles

How Muscles and Bones Interact

• Tendons: Join skeletal muscles to bones

• Most Skeletal muscles work in pairs. When one contracts the other relaxes.

Muscle and Bone Interactions

The Integumentary System

• Latin word integument means “to cover”

• Skin and its related structures (hair, nails, and glands) make up the integumentary system.

• Function: barrier against infection, helps regulate body temp, removes waste, protects from UV rays.

The Skin

• Skin is the largest organ in the body.– Two main layers:

• Epidermis• Dermis

• Epidermis– Outer layer of skin– Outside of epidermis is dead skin cells– Inner Layer is living cells– Contains melanin– No Blood Vessels

The Skin

• Dermis– Inner Layer of Skin– Contains blood vessel, nerve endings, glands,

sensory receptors, hair follicles, and smooth muscles.

– Major Glands: Sweat and Sebaceous (oil)• Sweat cools your body when it evaporates

• Oil keeps skin flexible and waterproof.

The Circulatory System

• The circulatory and respiratory systems, together, deliver oxygen to the entire body.

• Humans have a CLOSED circulatory system blood is contained within vessels

• Components: Heart, blood vessels, and blood.

The Heart

• Located at the center of the chest.– Structure of heart:

• Made up of muscle• Myocardium: Thick layer of muscle in the heart• Divided into four chambers

– 2 Atria and 2 Ventricles» Atria receive blood» Ventricles pump it out

• Has valves: flaps of connective tissue that prevent backflow.

Structure of the Heart

Circulation through the body

• The heart functions as two separate pumps– Pulmonary Circuit: Blood pumped to the

lungs– Systemic Circuit: Oxygen-rich blood returns

to the heart and is pumped out to the body.

Circulation

Heartbeat

• How do all the cells in a heart know when to contract?

• How do they do it at the same time?• Every Contraction begins in a specific area of

the heart called the sinoatrial node (SA node). The signal then spreads but pauses for split second at another node (the AV node). Why?– To make sure the atria and ventricles alternate

contractions!

Blood Vessels

• Aorta: Largest blood vessel that lead blood to the rest of the body.

• Three types of blood vessels:– Arteries: carry blood away from the heart

• Most are oxygen rich• Have thick walls to withstand pressure

– Capillaries: smallest blood vessels• The place where gas and nutrient exchange happens• Surround cells and Tissues

– Veins: Carry blood to the heart

Blood Vessels

Blood Pressure

• Blood Pressure is the force of blood on the walls of the arteries.

• Systolic/Diastolic– Systolic: Force in arteries when ventricles contract

– Diastolic: Force in arteries when ventricles relax

• Typical reading for a healthy person: 120/80

Blood

• The human body has 4-6L of blood.– 45% are blood cells– 55% is plasma

• Blood Cells– Three types of cells:

• Red Blood Cells

• White Blood Cells

• Platelets

Blood Components

• Red Blood Cells: Erythrocytes– Transport Oxygen– Hemoglobin: iron-containing protein in

RBC’s– Nuclei forced out during development– Very Numerous

Blood Components

• White Blood Cells: Leukocytes– Much less common– Contain nuclei– Attack bacteria, fight parasites, guard

against infection– Lymphocytes: Type of WBC that produces

antibodies to help destroy pathogens– Part of the immune system

Blood Components

• Platelets: Cell Fragments– Makes Clotting Possible– Positive Feedback system

Blood Components

The Respiratory System

• Respiration: the process of gas exchange– Release of Carbon Dioxide and uptake of

Oxygen

• The Human Respiratory System– Function: to bring about the exchange of

oxygen and carbon dioxide– Structures: nose, pharynx, larynx, trachea,

bronchi, and lungs.

The Human Respiratory System

• Air moves through the nose to a tube called the pharynx (or throat)

• From the pharynx, the air moves into the trachea, or windpipe.– A flap of tissue called the epiglottis covers the

entrance to the trachea when you swallow• At the top of the trachea, air passes through the

larynx, the voice box.• From the larynx, air passes into two large

passageways called bronchi.

The Human Respiratory System

• The bronchi divide into bronchioles which further divide into alveoli.– Alveoli: Membrane sacs containing the

capillaries for gas exchange– Alveoli is where gas exchange occurs!

• Hemoglobin: oxygen-carrying protein– Makes this process very efficient because

oxygen binds very well to it.

Breathing

• Breathing is the movement of air into and out of the lungs– No muscles in the lungs

• Diaphragm: Large flat muscle at the bottom of the chest cavity.

Respiratory Structures

How Breathing is Controlled

• Breathing can be voluntary

• It is controlled by the medulla oblongata in the brain.

Digestive System

• Food and energy– Energy is measured in calories.

• calorie: The Amount of heat needed to raise 1 gram of water by 1 degree celsius.

• Calorie: equal to 1000 calories. (The Dietary Calorie)

– Nutrition: The study of food and its effect on the body

Nutrients

• Nutrients: Substances the supply energy and raw materials for growth– Nutrients the body needs:

• Water• Carbohydrates• Fats• Proteins• Vitamins• Minerals

Nutrients

• Water– The most important nutrient because of the body’s

processes take place in water– Should drink at least 1 liter a day

• Carbohydrates– Main source of energy for the body– Simple (sugars) and complex (starch)

• Fats– Formed from a triglyceride– Two Types: Saturated and Unsaturated

Nutrients

• Proteins– Supply raw materials for growth and repair of

structures

– Made up of Amino acids (there are 20)

• Vitamins– The organic molecules that regulate body processes

– Two Types: Fat-Soluble (KADE) and water soluble.

• Minerals– Inorganic nutrients that the body needs

The Process of Digestion

• Function: convert food into simpler molecules that can be distributed to cells

• Parts of the digestive system: mouth, pharynx, esophagus, stomach, small intestine, and large intestine

• Accessory structures: salivary glands, pancreas, and liver.

The Mouth

• Mechanical Digestion: Physical Change– Teeth: Cutting, tearing, and crushing food

• Chemical Digestion: Chemical Change– Saliva contain an enzyme that begins

digestion of carbohydrates (Amylase).

Esophagus

• After chewing and slight chemical breakdown, the food (bolus) goes down the throat into the esophagus– Esophagus: Food tube connecting the pharynx to

the stomach

• Contractions of smooth muscles pull the food down, not gravity.– Peristalsis: Contractions of the smooth muscles that

moves food down to the stomach.

The Stomach

• Stomach: a large muscular sac• Chemical Digestion:

– Pepsin: enzyme that breaks down proteins– HCl in stomach creates acidic environment

• Mechanical Digestion:– Stomach muscles contract to churn and mix

fluids and food– Chyme: mixture in stomach

The Small/Large Intestine

• The Small Intestine– All of the absorption takes place in the small

intestine.– Villi: fingerlike projections lining the walls of the

small intestine– After absorption of nutrients, cellulose and other

indigestible items remain.

• The Large Intestine– Removes water from undigested material– Bacteria living there produces Vitamin K

Excretory System

• Excretion: The process by which metabolic wastes are eliminated

• Removing waste is part of maintaining homeostasis.

• Organs:– Lung, Skin, Liver, and Kidney

The Kidney

• The principal Organ of excretion• Function: Kidneys remove urea from the

bloodstream, maintain blood pH, regulate water content of blood, and regulate blood volume

• Ureter: A tube that leaves each kidney carrying urine to the bladder.

• Urinary bladder: Saclike organ where urine is stored before being excreted.

Kidney Structure

• Nephrons: The Functional Unit of the Kidney• Two process of blood purification:

– Filtration: passing a liquid or a gas through a filter to remove waste.

• Filtrate – the materials filtered through the blood (Ex: Glucose, salts, amino acid, water, urea and vitamins)

– Reabsorption: the process by which liquid is taken back into a vessel.

• After reabsorption, the remaining materials are called urine.

• Urine is stored in the bladder until it is released through a tube called the urethra.

Drugs and the Kidney

• Drugs often remain in Urine, which is why antibiotics and medications wear off after a while. It is also why drug tests are routinely performed on urine samples.

The Endocrine System

• The Endocrine System is made up of gland that release their products into the bloodstream that deliver messages throughout the body.– Hormones – the chemicals released in one part of

the body that travels through the bloodstream and affects the activities of cells in other parts of the body.

• Glands – an organ that produces and releases a substance or secretion

The Endocrine System

• Hormone Action – hormones belong to one of two groups:– Steroid Hormones

• Bind to DNA directly• Cause Dramatic Changes

– Nonsteroid Hormones• Bind to cell membrane.• Wide range of activities.

• Prostaglandins (local hormones) – Hormone-like substance produced by all cells that affect only nearby cells and tissues.

Control of the Endocrine System

• Regulated by feedback mechanisms that function to maintain homeostasis– Controlling Metabolism

• Thyroid

– Maintaining Water Balance• Kidneys

– Calcium Levels• Parathyroid

Human Endocrine Glands

• Pituitary Gland– Two parts: Anterior and Posterior– Secretes Nine Hormones– Master Gland

• Hypothalamus– Attached to the Posterior Pituitary– Controls the secretions of the pituitary

• Thyroid Gland– Located at the base of the neck and wraps around the trachea.– Regulates Metabolism

Human Endocrine System

• Parathyroid Glands– Four Glands located on the back of the surface of

the thyroid gland.– Maintains calcium levels

• Adrenal Glands– Two pyramid-shaped structures that sit on top of

the kidneys– Use to deal with stress– Fight or Flight hormone, epinephrine, is created in

the adrenals.

Human Endocrine Glands

• Functions as an exocrine gland by releasing hormones into the small intestine for digestion. Also functions as an endocrine gland by releasing hormones into the body– Maintain Blood Sugar Levels

• Abnormalities can lead to Diabetes Melitus.

Human Endocrine System

• Reproductive Glands– Gonads serve two important functions: the

production of gametes and the secretion of sex hormones

– Ovaries, for females, produces eggs, as well as progesterone and estrogen.

– Testes, for males, produce sperm and testosterone.

Endocrine Structures

The Immune System

• Disease is any change, other than an injury, that disrupts the normal functions of the body. Some are produced by pathogens, called infectious diseases.

Agents of Disease

• The human body provides the right conditions for many pathogens to grow:– Suitable Temperature– A watery environment– Plenty of Nutrients

• Pathogen causes disease by:– Releasing Toxins– Blocking Blood Flow– Removing Nutrients– Disrupting bodily functions

Disease Chart

Viruses

Protists

Worms

Fungi

Disease Agent That Causes Disease

Method of Transmission

Common cold

Influenza

Chickenpox

Measles

Tuberculosis

Meningitis

CholeraTetanusAfrican sleeping sicknessMalariaAmoebic dysenterySchistosomiasisBeef tapeworm

Athlete’s foot

Ringworm

RhinovirusTwo types (A, B), plus subtypesVaricella

Paramyxovirus

Mycobacterium tuberculosisNeisseria meningitidisVibrio choleraeClostridium tetaniTrypanosoma

PlasmodiumEntamoeba histolyticaSchistosomaTaenia saginata

Imperfect fungi

Imperfect fungi

Airborne; direct contact with infected personAirborne; droplet infection; direct contact with infected personAirborne; direct contact with infected personDroplets in air; direct contact with secretions of infected personDroplets in air; contaminated milk and dairy products

Direct contact with a carrier

Contaminated drinking waterContaminated wound; usually puncture wound

Spread by tsetse fly

Spread by Anopheles mosquitoes

Contaminated drinking waterFreshwater streams and rice paddies Contaminated meat

Contact with infected personExchange of hats, combs, or athletic head gear with infected person

Pathogen Types

Bacteria

Examples

The Immune System

• Function: The Immune System fights infection through the production of specialized cells that inactivate foreign substances or cells.

Nonspecific Defenses

• Include physical and chemical barriers.1. First line of Defense – to keep pathogens

out of the body.2. Second Line of Defense – the inflammatory

response, which is a nonspecific defense reaction to tissue damage caused by injury or infection

1. The Immune system also releases chemicals that increase the core body temperature, resulting in a fever.

Specific Defenses

• An immune response will occur if a pathogen is able to get past the body’s nonspecific defenses.

• A substance that triggers this is called an antigen, such as a virus, bacteria, or other pathogen.

Specific Defenses

• Two types of lymphocytes recognize these specific antigens:– B cells – provide immunity against antigens

and pathogens in body fluids (out of body)– T cells – provide a defense against abnormal

cells and pathogens inside living cells.

Acquired Immunity

• Over 200 years ago, smallpox was one of the deadliest diseases of the day. Edward Jenner noticed that people who contracted a similar disease, cowpox, were immune to the smallpox disease.

• His Experiment: He injected a young boy with cowpox and watched him develop a the disease. Two months later he injected the same boy with smallpox and the boy did not develop the disease.

Acquired Immunity

1. Active Immunity – a person develops antibodies to a certain pathogen

– Can Occur when recovering from a disease or getting a vaccine.

– Vaccination – the injection of a weakened or mild form of a pathogen to produce immunity

• Stimulates the production of millions of plasma cells ready to produce specific antibodies.

Immune System Disorders

• Allergies– Allergies are the most common overreactions

of the immune system to antigens.– Allergen: Antigens that cause allergic

reactions

AIDS, an Immunodeficiency Disease

• AIDS results from a viral infection that destroys helper T cells.

• The Virus that causes AIDS – HIV (Human Immunodeficiency Virus)

• Because T cells are destroyed, the body cannot fight pathogens very well.– Opportunistic diseases – diseases that attack

a person with a weakened immune system.

The Nervous System

• The Nervous System controls and coordinates function throughout the body and responds to internal and external stimuli– Ex. Body Temperature and Infection

(Internal)– Ex. Burns and Environmental conditions

(External)

Neurons

• Messages are sent through the body in the form of electrical impuleses.

• Neurons: the cells that transmit electrical impulses.

• Three types of Neurons:1. Sensory2. Motor3. Interneurons

Neurons

1. Sensory – Carry impulses from the sense organs to the spinal cord and brain

2. Motor – carry impulses from the brain and spinal cord to muscles and glands

3. Interneurons – connect sensory and motor neurons.

Neurons• Structure of a neuron:

– Cell Body: largest part, contains nucleus– Dendrites: branched extensions of cell body

that carry impulses in toward cell body• Can have many dendrites

– Axon: long fiber that carries impulses away• Only have one axon

– Myelin Sheath: insulating membrane around axon

• Has gaps called nodes

Diagram

• The message jumps from node to node as it is passed down the axon.

Axon terminals

Myelin sheath

Nodes

Cell body

Axon

Nucleus

Dendrites

The Nerve Impulse

• A neuron is at a resting state until it receives a stimulus large enough to start a nerve impulse.

• An impulse begins when a neuron is stimulated by another neuron or by another neuron or by the environment.

The Nerve Impulse

• The impulse causes the movement of ions across the cell membrane through gates (channels).

• The reversal of charges (or nerve impulses) is an action potential.

• The action potentials move down the axon sending the message.

The Synapse

• At the end of the neuron, the impulse reaches an axon terminal. Here the message is sent to another cell very close to the axon terminal.– Synapse: The location at which a neuron can

transfer an impulse to another cell

The Synapse

• The axon terminal contains tiny sacs filled with chemicals that neurons use to transmit an impulse across the synapse to other cells. These chemicals are called neurotransmitters.

• The neurotransmitters diffuse across the synaptic cleft (the space) and attach to receptors on the receiving cell. This cues the gates to open for Na+ to come in and cause another action potential.

Divisions of the Nervous System

• Neurons are joined together to form a complex system called the Nervous System.

• Two major divisions:1. Central Nervous System (CNS)

2. Peripheral Nervous System (PNS)

Central Nervous System

• The control center of the body

• Function: Relays messages, processes information, and analyzes information

• Structure: Brain and Spinal Cord (which are protected by the skull and vertebrae)

The Brain

• Made up of about 100 billion neurons!!!• Structure

– Cerebrum• Largest region with large surface area

• Controls voluntary activities

• Divided into right and left hemisphere

• Hemispheres are divided into lobes

• Each hemisphere deals with the opposite side of the body

• Cerebrum has two layers gray matter and white matter

Brain

Brain PET

The Brain

• Cerebellum– Second largest region– Located at the back of the skull– Coordinates actions of muscles so movement is

smooth

• Brain Stem– Connects the brain and spinal cord– Two regions: pons and medulla oblongata– Regulates info passing between brain and spinal

cord

The Brain

• Thalamus– Between brain stem and cerebrum

– Receives messages from sensory receptors in body and relays info

• Hypothalamus– Just below the thalamus

– Control center for recognizing hunger, thirst, fatigue, anger, and body temp

– Coordinates the nervous and endocrine system

The Spinal Cord

• Function: Main communication link between brain and the rest of the body

• 31 pairs of spinal nerves branch out from the spinal cord sending messages to diff. parts of the body.

• Some information is processed in the spinal cord (not the brain)– Ex. Reflex: quick, automatic response to a stimulus

Peripheral Nervous System

• Function: Receives information from the environment and relays commands from the CNS to organs and glands.

• Divided into two divisions:– Sensory: Transmits impulses from the sense organs

to the CNS– Motor: Transmits impulses from the CNS to

muscles and glands• Further divided into somatic nervous system and

autonomic nervous system

Peripheral Nervous System

• Somatic Nervous System– Movement of skeletal muscles– Conscious Control

• Autonomic Nervous System– Regulates involuntary– Ex. Heart Rate Increasing– Two Parts: sympathetic and

parasympathetic

Sympathetic Vs. Parasympathetic

The Senses

• Sensory Receptors: Neurons that react to a specific stimulus such as light or sound

– Located throughout the body but concentrated in the sense organs eyes, inner ears, mouth, nose, and skin.

• Five general categories of sensory receptors:1. Pain receptors (Nocireceptors)2. Thermoreceptors3. Mechanoreceptors4. Chemoreceptors5. Photoreceptors

Vision

• Structure of the eye:– Cornea – focuses light– Iris – colored part of the eye– Pupil – small opening in the iris, regulates

the amount of light passing into the eye– Lens – changes shape to adjust focus– Retina – inner layer of eye that contain the

photoreceptors

Vision

• Two types of photoreceptors– Rods: see black and white– Cones: see color and detail

• The place in your eye where the optic nerve goes to the brain there are no rods or cones blind spot

The Eye

Choroid

Retina

Blood vessels

Optic nerve

Fovea

Vitreous humor

Sclera

Ligaments

Iris

Pupil

Cornea

Aqueous humor

Lens

Muscle

Rods and Cones

Hearing and Balance

• Function of ear: Hearing and Positional change associated with movement (balance)

Hearing

• Sound is vibration in the air– Ears distinguish the pitch and loudness of the vibrations

• Structure of the ear:– Auditory Canal: place where vibrations enter– Tympanum (eardrum): vibrates– Bones: three small bones pick up vibrations from eardrum– Cochlea: fluid-filled place in ear, lined with hairs that move

from vibrations transmitted there.

• The hairs moving produce nerve impulses that go to the brain.

Balance

• Semicircular canals: Three tiny canals above the cochlea– They monitor position of your head

Ear

Auditory canal

Tympanum Round window Eustachian tube

Bone

Cochlea

Cochlear nerve

Semicircular canals

Oval window

StirrupAnvilHammer

Smell and Taste

• Chemoreceptors in your nasal passageway detect chemical and send impulses to your brain.

• Taste is also a chemical sense– Taste buds: sense organs that detect taste

• Located on surface of tongue and mouth

• Much of taste has to do with smell also

Tongue and Taste