Final Review

What is homeostatic regulation and why is its physiological importance?

Homeostatic regulation is the process by which the body maintains a stable internal environment (temperature, pH, blood sugar, water levels). It uses feedback mechanisms (negative moves towards homeostasis, positive continues moving until the desired response is achieved). It’s physiological importance is that stable internal conditions are necessary for cells and organs to work properly in the human body.

Compare positive and negative feedback and provide examples.

Positive Feedback Loops: pushing for further change away from homeostasis until desired outcome is reached

• childbirth: contractions stimulates release of oxytocin, which causes stronger contractions until baby is born

Negative Feedback Loops: reverses change to bring body back to homeostasis

• shivering when cold

• sweating when hot

Why is injury to the medulla oblongata frequently fatal? Provide 3 reasons.

An injury to the medulla oblongata is frequently fatal due to its control of vital functions of life including:

• respiratory control: breathing

• cardiovascular control: heart rate and blood pressure

• reflex centers: swallowing, coughing, vomit reflexes

Which is likely to heal faster, a bone injury or a cartilage injury? Why?

A bone injury is more likely to heal faster than a cartilage injury because bones have a good blood supply. The blood supply brings oxygen and nutrients to the bone cells for repair. Cartilage has very little blood supply so often heals slowly or not completely.

Identify at least three major functions of the integumentary system.

• protection: our skin is our first line of defense

• temperature regulation: sweat/blood flow

• sensory perception: detecting touch, heat, pain, cold

Identify at least three functions of the skeletal system.

• support: provides structural framework for body to maintain shape

• protection: shields organs

• movement: works with muscles to enable body movement

• produces blood cells

• stores minerals and lipids

Compare compact bone and spongy bone with regard to structure and function.

Compact Bone:

• dense and solid, made of osteons

• forms outer layer of bones

• provides strength and support

Spongy Bone:

• porous/light network of trabeculae with spaces filled with red bone marrow

• found inside bones, at ends of long bones and in interior of flat bones

• reduces bone weight, supports bone marrow, absorbs shock

• less dense

How could x rays of the femur be used to determine whether a person has reached full height? 

To determine if a person has reached full height, doctors check x-rays for the epiphyseal plate (growth plate) at the end of the femur. If this area has a dark gap visible, growth is still possible. if it is “fused” into a solid white line (epiphyseal line), the bone can no longer lengthen as it was where cartilage used to be.

Billy is injured during a high school football game. His chest is badly bruised and he is experiencing difficulty in breathing. What might the problem be?

Difficulty breathing and a severe chest bruise indicates potential for a few different serious issues:

• rib fractures: chest moves inward during inhalation instead of outword due to “paradoxical breathing”

• collapsed lung (pneumothorax): air leaking into plueral cavity from the puncture

• pulmonary contusion: a “bruise” of the lung tissue itself where blood is leaking into lung air sacs

• hemothorax: pleural space fills with blood instead of air, compressing lung

Six weeks after Fred broke his leg, the cast was removed. As he steps down from the exam table, his leg gives way and he falls. Propose a logical explanation.

Fred’s leg gave away because of disuse atrophy, where his muscles weakened and lost mass after lack of activity while in the cast. His body’s sense of balance and position was temporarily impaired, making his nervous system unable to properly coordinate strength in order to support his weight.

Compare the structure and function of arteries, veins, and capillaries.

arteries: thick, muscular walls to carry high-pressure blood away from heart

veins: thinner walls and valves to return low-pressure blood to the heart

capillaries: smallest vessels, having single-cell thick wells for efficient nutrient, gas, and waste exchange between blood and tissues

Compare the heart of a trained athlete and non-athlete.

In a trained athlete, their heart may be enlarged, resting heart rate is lower, more blood per beat, and faster recovery time. (Larger, stronger, and more efficient)

In a non athlete, heart size is normal, resting heart rate is average, blood per beat is normal, and recovery time is slower.

Compare and contrast the blood contained within the pulmonary arteries to the blood within the systemic arteries.

pulmonary arteries: low-oxygen (deoxygenated) blood from the hear to the lungs

systematic arteries: high-oxygen (oxygenated) blood from the heart to the rest of the body

In a healthy person, where is blood pressure greater in the aorta or in the inferior vena cava? Why?

Blood pressure is greater in the aorta because the aorta receives blood directly from the left ventricle, creating high pressure to propel blood throughout the body. The inferior vena cava returns blood to heart under very low pressure near zero.

List the three types of skin grafts. Which one is the best and why?

autograft: skin taken from patient’s own body

allograft: skin taken from another person

xenograft: skin taken from a different species

an autograph is the best for healing because it does not get rejected by the patient’s body and will grow with the body.

In some cultures, females must be covered from head to toe when they go outdoors. Explain why these women are at increased risk of developing bone problems later in life.

Covering the skin prevents enough sunlight from reaching it, so there is a Vitamin D deficiency. This leads to weaker bones and increases bone diseases such as osteoporosis later in life

What is the difference between ossification and calcification?

ossification: process of bone formation, where cartilage and connective tissue is replaced by bone.

calcification: deposition of calcium salts in any soft tissue; does not always mean bone is being formed

In a condition known as sunstroke, the victim appears flushed, the skin is warm and dry, and the body temperature rises dramatically. Explain these observations based on what you know concerning the role of the skin in thermoregulation.

The body becomes unable to dissipate heat effectively, and it is caused by vasodilation (blood vessels widen to push toward the surface). The sweat glands have stopped working.

Why is the sheep brain shaped differently than a human brain?

Sheep brains are shaped elongated for their 4-legged lifestyle, as human brains are larger, rounder, and highly folded. The brain stem of a sheep brain is more posterior, and the cerebellum is smaller. Sheep brains are designed for survival, whereas human brains adapted for complex cognition.

State the flow of blood through the heart starting with the vena cava. Include the 4 chambers, lungs, and blood vessels.

vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary veins → left atrium → left ventricle → aorta → body

What are the three reasons why fetal pigs are used for dissection in a human biology class?

1. organ systems are very similar to humans in structure and function

2. readily available and inexpensive

3. size and level of development make organs easy to identify and study

Why are the connective tissue wrappings of skeletal tissue important? Name these connective tissues and what structure it surrounds.

epimysium: surrounds each entire muscle

perimysium: surrounds fascicles (groups of muscle fibers)

endomysium: each muscle fiber (cell)

They are all important because they support, protect, and organize muscle fibers. They enable efficient contraction, and provide pathways for nerves and blood vessels.

Jeff is interested in toning his abdomen. What  three muscles would you tell Jeff to exercise to accomplish his goal? What movements would best exercise these muscles?

Jeff should focus on the rectus abdominis, external obliques, and transversus abdominis.

rectus abdominis: sit-ups, crunches

external obliques: russian twists, bicycle crunches, side planks

transversus abdominis: planks, vacuum exercises

Identify three functions of the muscular system. 

1. movement

2. stability + posture (support)

3. heat generation/body temperature