Summative Two Review

Exam Overview

This session is a support lecture focused on preparing you for Summative Two, which is an online test assessing knowledge from lectures and lab practicals throughout the year.

Exam Details

• Format: Online test

• Duration: Maximum of 2 hours to complete once started

• Test Window: 24 hours

• Date/Time: May 6, 1 PM to May 7, 1 PM

• Location: To be done at home with available resources.

• Questions: Three questions in total. One question must be chosen from the first section and two from the second section.

• Word Limit: 500 words per question (+/- 10%)

• AI Policy: AI is not permitted.

• Referencing: Use references throughout your answers.

Module Content Review: Key Systems

Cardiovascular System

• Anatomy: Labeling structures (ventricles, valves, atria, muscle layers).

• Physiology: Describing how the system works.

• Exercise: Explaining changes in the system due to exercise.

• Details: Sarah covered the initial components of the cardiovascular system, and later lectures discussed autonomic control during exercise.

Endocrine System

• Hormones: Key organs release different hormones.

• Examples: Sex hormones, insulin (pancreas), adrenaline (sympathetic nervous system).

• Thyroid Gland: Thyroxine for basal metabolic rate and energy metabolism.

• Parathyroid Hormone: Important for bone health.

• Pineal Gland: Also covered.

Respiratory System

• Anatomy: Labeling the lung and alveoli.

• Physiology: Understanding diffusion, Bohr effect, and their importance.

• Exercise: How responses change with exercise, including volumes and movement.

Nervous System

• Steady-state and incremental exercise lectures were conducted

Bone and Bone Health

• Stress fractures and risks, especially in female athletes with low bone mineral density were discussed.

Skeletal Muscle

• Excitation-contraction coupling was covered in detail.

Applied Lectures

• Altitude: Effects of altitude on the body were discussed.

• Heat: Effects of exercising in the heat and hyperthermia were explained.

Exam Structure: Section Breakdown

The exam is divided into two sections. In the first section, you choose one question out of three, typically involving anatomy (labeling a structure). The second section requires you to choose two questions out of three.

Sample Question 1: Bone Structure and Function

This question type includes multiple parts:

1. Labeling: Labeling different structures on a diagram (e.g., proximal and distal epiphysis).

2. Identification and Function: State the type of bone of labeled structures, identifying its characteristic shape and two functions of each.

3. Written Response: Describing physiological processes and purpose of bone remodeling with references.

Bone Structure Labeling:

• Proximal and Distal Epiphysis: Head of the bone and the other end

• Cortical Bone: Hard, shiny bone on the outside

• Trabecular Bone: Spongy bone in the middle

• Articular Cartilage: Prevents wear and tear on the bone

• Periosteum: Outer layer of the bone

• Endosteum: Inner layer of the bone

• Medullary Cavity: Contains yellow bone marrow (nutrients and fats)

Bone Types, Shape, and Functions

• Long Bones

  • Shape: Longer than they are wide, typically cylindrical

  • Functions: Facilitating movement when muscles contract (leverage) and supporting body mass when standing

• Irregular Bones

  • Shape: Irregular shape; don't fit into other categories

  • Functions: Protecting the spinal cord (vertebrae), eating/talking (jaw bones)

• Short Bones

  • Shape: Similar height and width, found in wrists and feet

  • Functions: Providing support and stability

• Flat Bones

  • Shape: Thin and curved

  • Functions: Attachment points for muscles (high surface area), location for red bone marrow (producing red cells, white cells, platelets)

• Sesamoid Bones

  • Shape: Typically shaped like sesame seeds (patella is the largest)

  • Functions: Protecting tendons from compressive forces, relieving tension, changing the angle of tendons for force production

Bone Remodeling

Bone turnover is regulated by:

• Osteoblasts: Bone forming

• Osteoclasts: Bone resorbing (breaking down bone)

• Osteocytes: Orchestrators of bone remodeling

The purpose of bone remodeling includes:

• Strengthening bones by building more bone than breaking down.

• Adjusting bone density based on use, e.g., bone breakdown occurs when a limb is immobilized.

• Replenishing about 10% of bone each year (cite reference).

• Maintaining bone's roles in protection and movement.

• Maintaining/losing bone mineral density depending on the balance between bone formation and breakdown.

Specific Cell Roles

• Osteoblasts: Make bone (refer to lecture slides for the process).

• Osteocytes: Act as mechanoreceptors; high forces encourage new bone formation; interconnected.

• Osteoclasts: Break down bone by secreting acid to dissolve minerals.

The bone remodeling cycle involves bone breakdown and new bone formation.

Sample Question 2: Incremental Cycling Exercise

This question asks to describe both the protocol and the physiological responses of incremental cycling exercise to exhaustion.

Protocol

• Incremental step protocol on a Monarch exercise bike.

• 3-minute test at 60 watts (60 RPM, 1 kg flywheel).

• Increase intensity by 30 watts (0.5 kg) every minute while maintaining 60 RPM until exhaustion.

• 3-5 minute cool-down at 60 watts.

• Goal: Participant reaches fatigue around 8-10 minutes.

Measurements

• Rating of Perceived Exertion (RPE): Recorded at the end of each minute.

• Heart Rate: Measured at the end of each minute.

• Expired Gases: Collected in the final 30 seconds of each minute using Douglas bags and a Harvard mouthpiece.

Equipment for Analysis

• Fractional content of oxygen and carbon dioxide measured using Servomex 5200.

• Gas volumes of expired air measured using a Harvard dry gas meter.

Physiological Responses

ATP Demand

ATP needs to be resynthesized to meet the demands of working muscles. As exercise intensity increases, ATP resynthesis must increase.

Oxygen Consumption (VO2)

Delivering more oxygen to working muscles increases ATP resynthesis. $VO_2$ increases proportionally to work rate until exhaustion.

A plateau may be achieved at maximum, termed $VO<em>{2max}$. If no plateau occurs, it's called $VO</em>2$ peak.

Carbon Dioxide Production (VCO2)

$VCO<em>2$ increases proportionally to $VO</em>2$ during early exercise. The anaerobic threshold is when $VCO<em>2$ increases at a faster rate than $VO</em>2$.

• Anaerobic metabolism contributes to ATP resynthesis.

• Glucose breakdown produces hydrogen ions, buffered by bicarbonate and converted into carbon dioxide and water.

Heart Rate

Cardiac output increases to meet oxygen delivery demands, so heart rate increases proportionally to work rate.

Sample Question 3: Oxygen-Hemoglobin Dissociation Curve

Using the oxygen-hemoglobin dissociation curve, explain why hemoglobin has a high affinity for oxygen at the lungs and a low affinity for oxygen at the working muscle during exercise.

Oxygen-Hemoglobin Dissociation Curve

• The red line shows the relationship between partial pressure of oxygen and hemoglobin saturation at 37 degrees Celsius and a pH of 7.4.

• The curve can shift left or right depending on conditions.

Curve Shifts

• Shift to the Right: More acid, more $CO_2$, more 2,3-DPG (glycolysis intermediate), or higher temperature.

• Shift to the Left: Lower temperature, more alkaline, less hydrogen, less carbon dioxide, and less of that glycolysis product.

Muscle Tissue

• Partial pressure of oxygen drops to around 40 mmHg at the muscle tissue.

• During exercise, the body extracts as much oxygen from the blood as possible.

• The oxygen-hemoglobin curve shifts to the right due to:

  • Increased Muscle Temperature: Heat from ATP breakdown.

  • Increased Hydrogen Ions: Acid production during exercise.

  • Increased $CO_2$: Produced during exercise.

  • Increased Glycolysis: More glycolysis occurring.

At the muscle tissue, the curve shifts right, causing hemoglobin to release oxygen.