Biology 20 - Unit D1: Human Systems (Respiratory and Motor Systems) (Questions)

Chapter 9 terms + big concepts

What are the stages in respiration?

Breathing, external respiration, internal respiration, cellular respiration

Explain external respiration.

Oxygen is diffused from a high concentration in the lungs to a low concentration in the blood to be used, and carbon dioxide is diffused from a high concentration in the blood (waste product of cellular respiration) to a low concentration the lungs to be breathed out

Explain internal respiration.

Oxygen is diffused from a high concentration in blood from the lungs to a low concentration in cells to be used in cellular respiration, and carbon dioxide (waste product of cellular respiration) is diffused from a high concentration in the tissues to a low concentration in blood going to the lungs

How is the structure of alveoli specialized for efficient gas exchange?

Walls are extremely thin, large surface area in relation to volume, fluid lined which enables gas to dissolve, surrounded by numerous capillaries

Describe inhalation.

Diaphragm and intercostals contract, the diaphragm is forced down, the volume in the lungs increases which decreases the air pressure in the lungs, air pressure is greater outside the lungs and air rushes in from high pressure to low pressure

Why is inhalation considered an active process?

Active, the contraction of muscles uses energy

Describe exhalation.

Diaphragm and intercostals relax, the diaphragm is pushed up, the volume in the lungs decreases which increases the air pressure in the lungs, air pressure is greater inside the lungs and air rushes out from high pressure to low pressure

Is exhalation a passive or active process? Why or why not?

Passive, relaxing muscles requires no energy

How do respiratory gases behave in terms of diffusion?

Move from an area of high concentration/pressure to an area of low concentration/pressure

Why, even though they have opposing concentration gradients, do carbon dioxide and oxygen move independently?

Partial pressure of gases: individual gases exert their own pressure independently of the other gases present in a system

What can hemoglobin bonding sites carry?

Oxygen, hydrogen ions, carbon dioxide

What are the methods of transporting oxygen? (Bonding)

Oxygen moves into hemoglobin and occupies a bonding spot to become oxyhemoglobin, oxygen dissolves into the blood

What are the methods of transporting oxygen? (Dissolved)

Oxygen dissolves into the blood

What are the methods of transporting carbon dioxide? (Dissolved)

Carbon dioxide is dissolved in the blood plasma

What are the methods of transporting carbon dioxide? (Dissociation)

Carbon dioxide dissociates into bicarbonate and hydrogen ions and H+ binds to proteins in blood plasma or hemoglobin

What are the methods of transporting carbon dioxide? (Binding)

Carbon dioxide binds to hemoglobin to form carbaminohemoglobin

Why does acidity of blood need to be buffered?

As carbon dioxide dissolves into the blood plasma it creates carbonic acid, thus the blood becomes more acidic, but the blood must be maintained at a near neutral pH or sickness and death may occur

What are the ways that the acidification of blood is buffered? (H+ Ions)

Free hydrogen ions from the dissociation of carbonic acid in red blood cells help to dislodge oxygen from hemoglobin and bind with hemoglobin/plasma proteins, thus removing hydrogen ions from solution

What are the ways that the acidification of blood is buffered? (Bicarbonate Ions)

Free bicarbonate ions from the dissociation of carbonic acid are released to the blood plasma and have a buffering effect there

What are the ways that the acidification of blood is buffered? (Carbonic Anhydrase)

Carbonic anhydrase helps to load more carbon dioxide into red blood cells and less into the blood plasma, thus less carbon dioxide dissolves into the plasma to contribute to acidification of the blood

What is the most common way CO2 is transported?

Dissociation of carbonic acid sped up by carbonic anhydrase where H+ binds to hemoglobin

What is the least common way CO2 is transported?

Dissociation of carbonic acid where H+ binds to plasma proteins

What are the stimuli that change breathing rate?

Exercise, high altitude, carbon monoxide poisoning

What are the types of muscle tissue?

Smooth, cardiac, skeletal

Why are there so many mitochondria in skeletal muscle cells?

Lots of mitochondria is required to produce the required energy for muscle contraction

What causes striations?

Different types of filaments (actin/myosin)

Describe the composition of a sarcomere.

Thin/actin filaments form “hallways, and myosin heads on myosin filaments slide out/walk into these “hallways” when muscles contract/relax

What happens in a sarcomere when muscles contract?

Myosin filaments “walk” down the actin filament “hallways”, shortening the sarcomere length

What happens in a sarcomere when muscles relax?

Myosin heads detach from actin filament and slide out of the actin filament ”hallways”

Describe the sliding filament model of muscle contraction.

Regulatory proteins tropomyosin and troponin block myosin bonding sites on actin. When a neuron stimulates a muscle, the release of calcium is triggered and calcium ions bind with troponin which changes the shape of tropomyosin, causing it to move off of myosin binding sites. This provides myosin with access to actin. An ATP molecule binds to a myosin head, where it is hydrolyzed into ADP and a phosphate. The myosin head performs a power stroke in which it moves towards the center of the sarcomere, releasing the ADP and phosphate. The binding of another ATP to the myosin head allows it to detach from the actin filament to restart the cycle

What are the steps in muscle contraction?

A nerve stimulates the release of CA2+ from the sarcoplasmic reticulum, Ca2+ provides access actin binding sites for myosin, myosin heads attach then pull the actin filaments together which causes muscle contraction, Ca2+ is taken back to the sarcoplasmic reticulum via active transport, ATP causes myosin heads release from actin filaments and cause the muscle to relax

What are the characteristics of fast twitch muscle fibres?

Can reach peak tension quickly but fatigue quickly, low oxidative capacity, high glycolytic capacity, stronger than slow-twitch motor units, appear white due to low amount of myoglobin and low density of mitochondria

What are the characteristics of slow twitch muscle fibres?

Relatively slow contraction time, high oxidative capacity, low glycolytic capacity, suitable for low power long duration activities, appear red due to rich blood supply and high amount of myoglobin and high density of mitochondria

Which energy source provides ATP for muscle contraction? How?

Creatine phosphate in muscles breaks down to provide phosphate and energy needed by ADP to become ATP

Which energy source provides the main fuel source for short duration, high intensity exercise

Creatine phosphate

Which energy source provides the main fuel source for long duration, low to moderate intensity exercise/endurance sports?

Fatty acids/fat