HBS EOC SG (1)

Human Body Systems Exam Review

Lesson 1.1: Identity: Human Understandings

• The human body is composed of complex systems working together to maintain homeostasis.
• Directional and regional terms are used to describe the position of anatomical structures.
• Expected Skills:
  • Identify systems and structures involved in basic body processes.
  • Explain functions of different body systems and list major organs.
  • Describe how body systems are interconnected and necessary for life.
  • Show the relationship between multiple human body systems.
  • Explain how directional and regional terms pinpoint locations on the body.
  • Demonstrate correct use of directional and regional terms.
  • Illustrate key directional term pairs on a human body model.

1.1.a How do parts of a human body system work together to carry out a specific function?

1.1.b How do different human body systems work together to complete specific functions?

• Urinary System:
  • Kidneys: Filter blood and make urine.
  • Ureters: Transport urine.
  • Bladder: Holds urine.
  • Urethra: Releases urine.
• Nervous System:
  • Brain: Control center.
  • Spinal Cord: Information highway.
  • Peripheral Nerves: Carry signals to and from limbs.
  • Sensory Organs: Collect sensory information and send it to the brain (eyes, ears, taste buds).
• Immune System:
  • Thymus: Promotes production of WBCs.
  • Tonsils: Trap pathogens.
  • Appendix: Stores good bacteria.
  • Spleen: Filters blood.
  • Lymph Nodes: Filter lymph fluid.
  • Skin: Prevents pathogens from entering the body.
• Digestive System:
  • Teeth/Tongue: Break down and push down food.
  • Pharynx: Food/air tube.
  • Esophagus: Food tube.
  • Stomach: Breaks down food.
  • Small Intestine: Absorbs nutrients.
  • Large Intestine: Absorbs water.
  • Rectum: Holds waste (poo).
  • Anus: Releases waste (poo).
  • Accessory Organs:
    • Gall Bladder: Stores bile, releases into the small intestine.
    • Liver: Makes bile for the small intestine.
• Respiratory System:
  • Nasal Cavity: Opening to the outside.
  • Pharynx: Air & food tube.
  • Larynx: Voice box.
  • Trachea: Air tube.
  • Epiglottis: Prevents food from entering the air tube.
  • Bronchi: Branch into lungs.
  • Alveoli: Site of gas exchange with blood.
• Cardiovascular System:
  • Atria: Entrance halls for blood.
  • Ventricles: Pump out blood.
  • Arteries: Carry blood away from the heart.
  • Arterioles: Little arteries.
  • Veins: Bring blood to the heart.
  • Venules: Little veins.
  • Capillaries: Sites of exchange with tissues.
• Endocrine System:
  • Hypothalamus: Top boss.
  • Pituitary: VP.
  • Pineal Gland: Sleep/wake cycle.
  • Adrenal: Fight or flight response.
  • Thymus: Develops immune system.
  • Testes/Ovaries: Sex hormones.
  • Thyroid: Metabolic hormones.
  • Pancreas: Insulin.

1.1.c How can directional terms and regional terms help describe location in the body?

• Directional Terms:
  • Anterior (Front) / Ventral (Belly)
  • Posterior (Back) / Dorsal (Back)
  • Superior (Above) / Higher
  • Inferior (Below) / Lower
  • Lateral (Side) / Toward the side
  • Medial (Middle) / Toward the middle
  • Proximal (Far): On limb, nearer to attachment point
  • Distal (Near): On limb, farther from attachment point
  • Superficial (Above): More external, surface of body
  • Deep: More internal

1.1.d What features of structure and function are common to all humans?

• Humans can be told apart by the <0.1% that is different about us.
• Common features:
  • Four tissue types: Connective, epithelial, muscle, and nervous.
  • 23 pairs of chromosomes.
  • 206 bones at maturity.
  • DNA as identity molecule.
  • Bipedal.
  • Opposable thumbs.
  • Highly evolved cerebral cortex.
  • 24 ribs, 12 pairs.
  • Four-chambered heart.
  • Lungs dependent on outside pressure.
  • Little body hair.

Lesson 1.2: Identity: Tissue Understandings

• A tissue is a group of similar cells designed to carry out a specific function.
• Bones protect internal organs while allowing for movement and mobility.
• Bone structure reveals information about a person’s gender, stature, age, and ethnicity.
• The length of long bones can mathematically predict an individual's overall height.
• Expected Skills:
  • Identify characteristics of the four categories of human tissue.
  • Describe the functions of the human skeletal system.
  • Recognize that differences in bone structure contribute to a person’s unique identity.
  • Recognize the relationship between the length of long bones and overall height.
  • Analyze the structure of various human tissue types to infer function.
  • Identify and locate bones of the human skeletal system.
  • Interpret bone markings, landmarks, and measurements to determine gender, age, stature, and ethnicity.
  • Derive and analyze a linear equation.

1.2.a What are the main types of tissue in the human body?

1.2.b How does the structure of a type of human tissue relate to its function in the body?

• Tissues are collections of similar cells that perform a common function. A group of tissues is called an organ.
  • Epithelial: Covers, lines organs and body cavities, layers (one kind of cells inside & a different kind outside).
  • Muscle: Moves, makes up all muscles, including the heart, long and narrow so they can contract to allow movement.
  • Nervous: Signals, includes neurons & neuroglia, long axons to allow signals to travel distances, branches for connections.
  • Connective: Joins, adipose (“fat”), blood, bone, cartilage, etc., fairly consistent matrix to allow it to fill spaces of various shapes/sizes.

1.2.c How does the distribution and structure of different types of tissue in the body contribute to personal identity?

• Some people have more muscle & some have less.
• Differences in nerves & nerve connections affect the way our minds work and they ways we make decisions.
• Some people have more connective tissue. For instance, an obese person has much more adipose than a thin person.
• Most cells contain a central nucleus that contains DNA and every person’s DNA is completely unique (except identical twins).

1.2.d What are the functions of the human skeletal system?

• The axial skeleton (skull and trunk) protect soft organs such as the brain, heart, lungs, etc.
• The appendicular skeleton (arms and legs) provides attachment points for muscles that allow movement.

1.2.e What are the main bones of the human skeletal system?

• Cervic = neck
• Crani = skull
• Vert = to turn
• Thorac = chest
• Fibul = outer bone of leg
• Meta = between
• Tars = instep, ankle
• Carpal = wrist
• Pel = push
• Clav = collarbone
• Pariet = wall
• Zyg = join
• Occ = eye

1.2.f What is forensic anthropology and how does this field relate to human body systems?

• Forensic anthropology is the study of human bones to determine information about the deceased and decide the cause of death and whether a crime was committed.
• Forensic anthropologists are not generally medical doctors, but instead usually have a PhD. They tend to be college professors and have 12+ years of education.
• When a deceased person still had flesh, the job usually goes to a Medical Examiner, but when only bones are located, the job is done by a Forensic Anthropologist.

1.2.g How can features of bone be used to determine information about a person’s gender, ethnicity, age, or stature?

• Gender can best be determined from skull or pelvis

  • Males: Square eye sockets, u-shaped mandible, brow ridges & sharper heart-shaped pelvis, angled-in coccyx.
  • Females: Round eye sockets, v-shaped mandible, smoother bones, rounded pelvis, wider pubic arch.

• Skulls (esp. nasal index) are best determinant of race.

• Bone fusion (especially) in the pelvis is the best predictor of age (older = more fused)

• Humerus and femur length are the best predictors of height.

Lesson 1.3: Identity: Molecules and Cells

• Human DNA is a unique code of over three billion base pairs.
• Restriction enzymes recognize and cut specific sequences in DNA.
• Gel electrophoresis separates DNA fragments based on size and is used in RFLP analysis.
• Physical characteristics can be used to confirm or authenticate identity.
• Expected Skills:
  • Explain how restriction enzymes cut DNA.
  • Describe how gel electrophoresis separates DNA fragments.
  • Recognize that gel electrophoresis can be used to examine DNA differences between individuals.
  • Outline current biometrics technology.
  • Digest DNA samples using restriction enzymes.
  • Demonstrate gel electrophoresis steps and analyze the resulting RFLPs.

1.3.a What is the structure and function of DNA?

• DNA stands for deoxyribonucleic acid.
• It is a double-stranded helical molecule that the chromosomes in the nucleus of our cells are made of.
• DNA makes up genes, which make up chromosomes.
• Each gene codes for a protein (like hemoglobin), and each protein determines a trait (like oxygen-carrying red blood cells).

1.3.b How does DNA differ from person to person? 1.3.c What role does DNA play in our identity?

• More than 99.9% of the DNA of each person matches the DNA of every other person. Scientists can analyze the small bits that differ to determine who DNA came from, though.

1.3.d How can tools of molecular biology be used to compare the DNA of two individuals?

• DNA can be extracted from a person & then scientists can perform PCR to amplify the DNA.
• They can then cut the DNA with restriction enzymes and run the samples through gel electrophoresis to analyze the size of each DNA fragment.
• Because the DNA of each individual is unique, the restriction enzymes will cut each person’s DNA in a different place, so the RFLPs will look different on the gels.

1.3.f What are restriction enzymes?

• Restriction enzymes come from bacteria (mostly) and are chemicals they are thought to use to break down the DNA of invading viruses.
• Geneticists use them to cut DNA into smaller fragments called Restriction Length Polymorphisms.

1.3.g What are restriction fragment length polymorphisms?

• RFLPs are the bits of DNA after the long strand has been cut by restriction enzymes. They’re what we see on the electrophoresis gel.

1.3.h What is gel electrophoresis and how can the results of this technique be interpreted?

• Gel electrophoresis is how RFLPs get separated.
• DNA molecules have a negative charge (because of the phosphates).
• They are attracted to a positive charge.
• DNA samples are placed in wells within an agarose gel near a negative electrode.
• When the electricity is started, they move toward the positive electrode.
• Smaller bits are lighter and travel faster, so the bits get separated by size. This makes it possible to tell individuals apart.

1.3.i How can the field of biometrics be used to verify and protect identity?

• DNA analysis is one form of biometrics and can be used to tell individuals apart.
• Only identical twins have 100% identical DNA, so for everyone else our DNA is as unique as our fingerprints.
• Other forms of biometrics include iris scans, voice analysis, fingerprinting, gait measurement, facial recognition, etc.
• They can be used to protect accounts, protect babies and national security, etc.

Lesson 2.1: The Brain

• Communication between body systems is crucial to maintaining homeostasis.
• The brain receives stimuli from the outside world, interprets this information, and generates an appropriate response.
• Each region within the brain helps control and regulate specific functions in the body.
• Expected Skills:
  • Describe the structure and function of the central and peripheral nervous systems.
  • Identify major regions of the human brain.
  • Match regions of the brain with their primary function.
  • Apply knowledge of brain structure and function to specific human actions, emotions, and/or dysfunctions.
  • Interpret the impact of communication breakdown in the central nervous system on the human body.

2.1.a. What is communication?

• Communication is messages passing from one entity to another & being understood by the 2nd entity.

2.1.b. What are ways communication occurs in machines and in the human body?

• Machines: My computer is powered by electricity. Somehow the vibrating electrons cause the computer to turn on & the binary code stores and transmits messages for how programs run.
• Human Body: Communication can be chemical (endocrine system, hormones) or electrical (nervous system, impulses)

2.1.c. What are consequences of miscommunication in the body?

• When there is miscommunication within our central nervous system (brain, brain stem and spinal cord) we might misunderstand sensory input or our body’s might do things we don’t want them to (uncontrolled movements, lack of balance, paralysis, mental illness, etc)

2.1.d. How do the central nervous system & the peripheral nervous system work together to control the body?

• Sensory input: Sense information is carried to the brain. Information from the eyes/ears goes directly to the brain. However, information from the lower body is first picked up by the peripheral nervous system (PNS) & then passed into the spinal cord, then through the brain stem & then into the brain (all parts of the central nervous system or CNS).
• Motor output: Muscle movement is mostly started in the CNS (unless it’s a reflex response) and then the impulses travel through the brainstem into the spinal cord and to the PNS to activate the neurons in the muscles that need to move.

2.1.e. What are the functions of the main regions of the brain?

• The cerebellum mostly controls fine motor movement & balance.
• The cerebrum is higher thought.
• The gyri are the ridges between grooves/furrows (sulci) and get deeper with learning.
• The limbic system controls emotions & motivation.
• There are 4 major lobes (divisions)—frontal, occipital, temporal & parietal.

2.1.f. How do scientists determine which areas of the brain are associated with specific actions, emotions or functions?

• Earliest attempts: Based on phrenology, which used bumps on the skull to determine personality traits.
• Then & now: Study patients with brain injuries. The area of the injury can be linked to changes in behavior or abilities (i.e. Phineas Gage’s damaged frontal lobe caused personality changes).
• Now: MRIs & electrodes directly implanted into the brain can show which areas of the brain are active during which activities or even when people are thinking about various things.

Lesson 2.2: Electrical Communication

• Neurons convey information using electrical and chemical signals.
• The body’s reaction time to reflex and voluntary actions is related to processing in the nervous system.
• Errors in electrical communication can impact homeostasis in the human body.
• Expected Skills:
  • Recognize the role of neurons in passing signals to and from the brain and spinal cord.
  • Describe how ion movement across the neuron cell membrane generates an action potential.
  • Explain how neurons communicate at the synapse.
  • Describe differences in brain processing for reflex and voluntary responses.
  • Outline the process from initial stimulus to response.
  • Analyze experimental data to explore reaction time and reflexes.
  • Design an experiment to test factors impacting reaction time.
  • Analyze case studies to determine the effects of a communication breakdown in the nervous system.

2.2.a How does communication happen within the body?

• Electrical Signals: Nervous System
• Chemical Signals: Endocrine System
• The nervous system is made up of neurons.
• Neurons communicate just like people do, but they send messages using action potentials (electricity passing through their axons).
• Each neuron picks up signals at its dendrites, passes the signals down the axon, into the axon terminals, and into the synapses.
• The synapse then drops neurotransmitter into the synaptic cleft between the first neuron’s synapse and the next neuron’s dendrites. That signals neuron #2 to pass the message on.

2.2.b What is the basic structure and function of a neuron?

• Function: Sends electrical signals through body
• Structure:
  • Dendrites (“trees”): Pick up signal
  • Axon: Carry signal long distances (up to 3 ft)
  • Myelin Sheath: Insulates axon
  • Nodes (“knots”) of Ranvier: Allow nutrients in, waste out
  • Axon Terminals (“ends”): Branch to meet other neurons
  • Synapses: Place one neuron connects to next
  • Synaptic Cleft: Joint between neurons
  • Neurotransmitters (“to carry across a nerve”): Chemicals that allow neurons to communicate with each other

2.2.c How do the different types of neurons work together to send and receive signals?

• Sensory Neuron: Pick up signals through senses (sight, smell, touch, etc), send info from PNS to CNS
• Interneuron: Connect sensory neurons to motor neurons, found in CNS
• Motor Neuron: Receive signals from CNS, causing movement, in PNS, receive info from CNS

2.2.d How are electrical impulses created in the human body?

• $Na^+/K^+$ pump keeps the outside of the membrane + and the inside – by pumping positive ions out of the membrane, priming the membrane to carry charges
• During an action potential, there’s a sudden reversal of charge, carrying a message down the axis

2.2.e How do neurons convey information using both electrical and chemical signals?

• Electrical: Action potentials down the axis of each neuron (WITHIN each neuron)
• Chemical: Neurotransmitters conduct signals BETWEEN neurons

2.2.f What factors impact our ability to react to a stimulus?

2.2.g How and why does reaction time differ in reflex and voluntary actions?

• Reflex: Reflex responses simply go to the spinal cord and don’t involve the brain, so the reaction time is VERY fast (example: blinking when something comes at you, kicking when hit with reflex hammer)
• Voluntary: Voluntary responses must travel to the brain and take longer. The more thought that is required (i.e. doing the OPPOSITE of what asked), the slower the reaction time.

2.2.h How do errors in communication impact homeostasis in the human body?

• Epilepsy: Bursts of electricity cause involuntary responses (seizures, odd smells, etc)
• Parkinson’s: Cells that make dopamine die (no one knows why). The lack of this neurotransmitter causes problems in communication between neurons in the two brain regions that must communicate to allow smooth, controlled movements
• Huntington’s: Genetic defect on chromosome 4 (excess CAG repeats) causes synthesis of abnormal protein—the protein disrupts function of certain nerve cells, ultimately leading to their deaths (dead cells can’t communicate)
• Alzheimer’s: Brain cells die (cause unknown) and dead cells can’t communicate-communication breaks down, getting worse with time and eventually causing death
• Multiple Sclerosis: The immune system attacks the myelin around nerve axes in the brain, spinal cord, and optic nerves, causing nerves to be unable to transmit messages due to a buildup of scar tissue (sclerosis).
• Amyotrophic lateral sclerosis (Lou Gehrig's): Nerve cells waste away or die and can’t send messages to the lower motor neurons. Movement becomes less and less controlled. Eventually, the lung muscles cannot contract, causing death.

2.2.i How can biomedical professionals help treat, cure and improve the quality of life of those suffering from nervous system disorders?

• The main person that treats neurological disorders is a Neurologist.
• People with these disorders also rely on Pharmacists to dispense their medication, Nurses to care for them, Pharmacologists to produce new medications, researchers to help understand causes and possible treatments, Brain Surgeons if surgery is possible, Psychiatrists if they are depressed, Physical Therapists to maintain movement, etc.

Lesson 2.3: Chemical Communication

• The endocrine system helps the body communicate through chemical signals called hormones.
• Hormones help maintain homeostasis through feedback loops.
• A hormone imbalance can lead to disease or dysfunction.
• Expected Skills:
  • Describe how hormones interact with target cells.
  • Recognize the human body uses feedback mechanisms to maintain proper hormone levels.
  • Model a feedback loop that shows how the body maintains homeostasis.
  • Analyze physical symptoms of a patient and relate these symptoms to errors in chemical communication.

2.3.a What is a hormone?

• A hormone is a chemical (specifically a protein) secreted by an endocrine gland (gland is just a name for an organ that secretes something) that signals a system to do something.

  • Some hormones are short-term (like adrenalin speeding up heart rate) and some are long term (like growth hormone)
  • The same hormone can be secreted by multiple organs (for example, the ovaries and adrenal glands both make estrogen).
  • Very small amounts of hormones can have very large effects.

• Endocrine glands is another name for endocrine organs and they are found in the endocrine system.

• They include the pancreas, thymus, thyroid, pituitary gland, pineal gland, adrenal glands, ovaries and testes.

• Endocrine glands are found throughout the body, but are all ultimately controlled by the hypothalamus and pituitary gland in the brain.

• Below are examples of hormones and what they do.

  • Insulin: secreted by the pancreasregulates blood sugar levels by allowing cells to take in sugar
  • GH (growth hormone): secreted by pituitarystimulates growth
  • FSH (follicle stimulating hormone): secreted by anterior pituitarystimulates maturity, including sexual maturity
  • Glucagon: secreted by pancreasincreases sugar levels in blood
  • TRH: secreted by hypothalamustriggers pituitary gland to secrete TSH
  • TSH: secreted by pituitary glandtriggers thyroid gland to secrete T3/T4
  • T3/T4: secreted by thyroid glandregulate metabolism

2.3.b How do hormones interact with target cells?

• Each hormone travels in the blood looking for target cells.
• Target cells have receptors that the hormone fits into, like a key.
• For example, a male sex hormone would only fit receptors in cells in the male sex organ and would have no effect on other cells.

2.3.c What are examples of endocrine glands and exocrine glands in the human body?

• Cowper's glands
• Cobelli's glands
• Mammary glands |
  | | Product & Location |
  | | * Sweat, skin
• Pre-ejaculate, penis
• Mucus, esophagus
• Milk, breasts |

2.3.d How do feedback loops help regulate the action of hormones?

• Feedback loops keep hormones in balance.
• When hormone levels go ABOVE homeostasis, feedback loops REDUCE hormone levels.
• When hormone levels drop BELOW homeostasis, feedback loops bring them back up to normal levels.
• Examples of this include:
• Insulin & blood sugar
• T3/T4 & metabolism
• Growth hormone & growth

2.3.e How can too little or too much of a hormone lead to disease?

Hormones must be perfectly balanced for optimal health. Disease can result if they are too high or too low.

Lesson 2.4: Communication with the Outside World

• The structures within the human eye work to focus and process light.
• The eye allows perception of color, depth, brightness, and optical illusions.
• Errors in the structure and function of the eye can lead to problems in acuity or dysfunction.
• Problems with focusing light in the eye can be corrected with lenses.
• Expected Skills:
  • Identify the key structures of the eye.
  • Demonstrate how light is processed in the eye in a person with normal vision, as well as myopia or hyperopia.
  • Explain the tests and procedures in a typical eye exam.
  • Diagram the path of light as it enters the eyes and travels to the brain for processing.
  • Evaluate visual perception by testing depth perception, peripheral vision, color vision, and visual acuity.
  • Experiment with lenses to refocus light and correct vision problems.

2.4.a. How do humans communicate with the world around them?

• Humans take in information using their senses (sight, hearing, touch, taste & smell) & send out information using their ability to speak or using body language or movement.

2.4.b. How does the power of sight allow humans to communicate with the outside world?

• >80% of the data that we take in comes from our power of sight.
• Sight lets us take in 180 º of images, perceive 1 million different colors, adjust what we see based on level of light & focus close up or miles away.
• Our vision is more detailed than any digital camera.

2.4.c. How is light focused by the eye?

2.4.d. How do the eye and the brain work together to process what we see? 2.4.i. How does the eye perceive depth, color and optical illusions?

• Messages from the retina pass into the optic nerve and are carried to the visual cortex in the occipital lobe.
• There the image is flipped over and gaps are filled in.
• Our visual database (built during childhood) helps us interpret images.
• The retina is
  • >95% rods (found all over retina & used for seeing B/W, peripheral vision & low light viewing)
  • <5% cones (for COLOR PERCEPTION, concentrated in fovea, tiny spot with detailed vision)
• DEPTH PERCEPTION: Depends on the retina: The visual database contains information about the size of objects from previous experience & gauges size based on that. Moving the head from side to side allows you to see how far objects move. Comparing the image from one eye to the combined images tells the retina how far away something is.
• OPTICAL ILLUSIONS: These are examples of “visual deception” & trick the brain by using arrangement of images, color effects & light source impact to mislead the brain.

2.4.e. How does what we see impact other human body systems?

• From basic movements like walking (using skeletal and muscular system) to emotional responses to what we see (limbic system & endocrine responses), our sight guides our actions in many ways.

2.4.f. What is visual perception?

• Visual perception is the combination of what we see and how we interpret it.
• Sight without a visual database is useless and a visual database without sight is also useless.
  • Examples: Color perception, depth perception, visual acuity, peripheral vision

2.4.g. What does it mean to have 20/20 vision?

• 20/20 is considered “normal” visual acuity
• If your vision is 20/200 it means that you have to be 20 ft away to see something a human SHOULD be able to interpret from 200 feet away.
• 20/15 vision means that from 20 ft away, you can see what most people have to be 15 ft away to see.

2.4.j. How does an error in the structure or function of the eye relate to disease or dysfunction? 2.4.k. How is life impacted by a vision disorder? 2.4.h. How can corrective lenses be used to refocus light and resolve myopia and hyperopia?

2.4.l. What are the tests and procedures in a routine eye exam?

• Visual acuity test: Read the Snellen chart from across the room to measure clarity of view (acuity)
• Automated perimetry: Push a button when you see a flash to measure peripheral vision
• Refraction assessment: Look through Phoroptor to determine which lens works best for each eye
• Slit-lamp examination: Slit lamp focuses intense light on eye to determine abnormalities
• Indirect ophthalmoscopy: Doctor holds eye open & examines with a bright light (shows great detail and 3 dimensions)
• Applanation tonometry: Measures pressure needed to flatten part of cornea, tests for glaucoma

Lesson 3.1: Introduction to Power

• Many human body systems work to create, process, and distribute the body’s main resources – food, water, and oxygen.
  • Expected Skills:
  • List and describe the human body systems that create, process, and distribute food, water, and oxygen.
  • Recognize that factors unique to the person, such as age, weight, and overall health affect the body’s ability to utilize biological resources and maintain homeostasis.
  • Recognize