IB Sports Unit 2

Sensory function (1. In)

Detecting internal stimuli; increase in blood activity; 5 senses & inside body

Integrative function (2. Process)

Analyzing (& storing some) sensory info; make decisions for responses; Brain 99%, reflex(1%)

Motor function (3. Do gland or muscle)

Respond to integration decisions; motors/ efficient neurons carry info from brain to spinal cord/body parts

Structures/functions of the nervous system

1. Influence all functions in the human body

2. Senses internal & external conditions

3. Allow communion, coordination, & interaction of tissues, systems, and between the body and external environment

4. Is divided into 2 main divisions (Central NS, Peripheral NS)

Some things hypothalamus is responsible for

Maintaining homeostasis by regulating blood pressure, appetite control/food intake, heart rate, stroke volume, sleep-wake cycles, respiration, body temp, digestion, thirst, fluid balance, etc

Sympathetic NS

Fight or Flight response during sport or exercise. (Increase heart rate, metabolic rate, etc)

Parasympathetic NS

Regulate body’s involuntary function. Maintains homeostasis by promoting rest, relaxation, & conservation of energy. (Decrease heart rate)

Atrioventricular (AV) node

Conducts electrical pulse from the atria to the ventricles.

Extrinsic factors for heart control

Parasympathetic (lower heart rate)

Sympathetic (increase heart rate)

Endocrine (hormones) system (adrenaline)

How a stimulus brings a motor response

1. A sensory stimulus is received

2. Info travels along sensory nerves to CNS

3. CNS selects appropriate response

4. CNS sends message along motor nerves to skeletal muscles

5. Motor response occurs

Proprioceptors

Specialized cells located in muscles, tendons, joints, etc; Provide info about body position in space, muscle length, movement of joints. (Helps maintain balance)

Chemoreceptors

Detective chemicals in mouth, nose, and body fluids. Monitor O2, CO2, H+ in the blood. Alerts brain when there is disturbance

Baroreceptors

Pressure sensitive NC. Detect higher or lower blood pressure

Endocrine system

Regulates the body & controls the responses to physiological challenges. Release hormones from tissue/glands

Hormones

Chemicals that regulate the activities of other cells around the body. Can only interact with specific receptors for specific responses

Steroid (Hormone)

Fat soluble & pass through cell membranes to interact with receptors and elicit a response (Testosterone, Oestrogen, Progesterone)

Non-Steroid (Hormone)

Not fat soluble. Must interact with receptors on cell surface to trigger messenger chemicals inside the cell to elicit a response (Epinephrine, glycogen)

Prostaglandins

Non-steroid hormone produced in cell membrane close to site of action.

When are hormones released

When a direct stimuli is reacted

Neural (Hormone regulation)

Signals from the nervous system (Ex: Exercising = sympathetic NS increase epinephrine = increase cardiovascular)

Humoral (hormone regulation)

Relay info by responding to changes in chem of the blood (Ex: High blood glucose = increase insulin, Low blood glucose = increase glycogen)

Hormonal (hormone regulation)

Respond to changes in other hormonal levels (Ex: Empty stomach = increase appetite)

Why is pituitary gland = master gland

Is the most important endocrine and involved in maintaining homeostasis

Oestrogen (Joint Stiffness)

When oestrogen levels decrease = bone density loss = joint stiffness. Can influence production of synovial fluid. Helps reduce inflammation in joints

Oestrogen (Glycogen sparing)

Influence metabolism, muscular fitness, and body composition. Females rely on fat as source of fuel and spare more glucose

Progesterone (Thermoregulation)

Process by which body keeps a relatively constant temp over a wide range of environments and activity levels

Progesterone (Sleep Quality)

Calming & sedative effect = relaxation & drowsiness. (Promote sleep)

Homeostasis

The body’s ability to maintain constant internal environment

What does hypothalamus regulate

Blood pressure, heart rate, respiration, digestion, body temperature, thirst and fluid balance, strength of heart contractions, appetite, sleep cycle.

How does NS and endocrine work to together

NS regulates homeostasis by sending nerve endings to organs (quick). Endocrine has glands secreting hormones into blood (slow)

Feedback Mechanism

Stimulus → Sensors (receptors) → Control Center (Brain) → Effectors

Normal blood pH

7.35-7.45

CO2 is produced by

Cellular metabolism

Increase in CO2 =

Increase hydrogen ion = more acidic blood

To counter low blood pH

Respiratory control center increases rate & depth of breathing = restoring blood pH (negative feedback mechanism)

Intrinsic

Things in the heart that control how the heart beats

Sinoatrial (SA) node

Pacemaker; generates electrical impulses that cause heart contractions/pump blood. (Influenced by level of O2/CO2 & Hormones)

Extrinsic

Things outside the heart that affect heart contractions (Auto NS = Sympathetic & Parasympathetic)

Sympathetic NS on heart

Releases hormones that increase heart contractions = increase heart rate and cardiac output

Parasympathetic NS on heart

Release hormones that slow down SA node = decrease force of contraction, heart rate)

Response to too high blood sugar

Release insulin

When blood sugar gets too low

Release glucagon = promotes glycogenolysis

Insulin Sensitivity

Body needs less insulin to transport glucose cells. Exercise = uptake of glucose sensitivity by muscle cells

Insulin resistance

Pancreas produces more insulin to regulate blood sugar. Due to inactivity and high processed food.

Normal body temperature

37 +- 1 C

Where does all energy originate from

The sun (light energy)

ATP

Energy in food molecules bonds being released for muscle contraction

Muscle contraction is about…

20% efficient, 80% released as heat

Tc

Core body temperature

Shell temperature

The temp near the body surface

Metabolic rate and body heat

Increase metabolic rate = increase body heat

Ways to increase body heat/metabolic rate

Exercise, hormones, nervous system, body temp, ingestion of food, age, sex differences

4 ways heat can be transferred away from the body

Conduction, Convection, Radiation, Evaporation

Conduction

Heat generated internally can be conducted through body to clothes or air. Direct contact.

Convection

Moving heat from one place to another through the motion of air. (If cooler air = increase heat loss)

Radiation

Transfer of heat waves from one object and absorbed by another. (Body absorbs radiation heat when environment temp > skin temp)

Evaporation

Conversion of sweat to water vapor

What heat transfer method is most effective

Evaporation

Non-shivering thermogenesis

Sympathetic NS simulates increased metabolism = increase heat production

Shivering

Involuntary contractions of skeletal muscles to increase rate of heat production

Where are most sweat glands found

The back and chest

Sweating efficiency

Sometimes it isn’t evaporated and the amount of sweat produced can decrease in more humid areas

Sex differences in thermoregulation

Females: larger surface area to mass ratio = more heat produced

Males: higher sweat rate

Peripheral/Systemic Circulation

Blood pumped between heart and muscles

Pulmonary Circulation

Blood pumped between heart and lungs

Why does our respiratory and cardiovascular systems work together?

Maintaining homeostasis

Where will substance flow from

High pressure to low pressure

Mechanism of breathing (Inhale)

Diaphragm contracts downward = increase volume = decrease pressure = air rushes in

Mechanism of breathing (exhale)

Diaphragm contracts upward = decrease volume = increase pressure = push air out

Exercise effect on lungs

More energy needed = more O2 demand = increase blood acidity = increase lung volume during inhalation + faster lung compression

How does the structure of lungs facilitate gas exchange

1. Large Surface Area

2. Thin membranes

3. Surrounded by lots of blood vessels

Tidal Volume (Vt)

The amount of air inhaled and exhaled in a normal breath

Inspiratory reserve volume

The extra air that can be inhaled above the tidal volume (max inhale)

Expiratory reserve volume

The extra air that can be exhaled above the tidal volume (max exhale)

Vital capacity

The amount of air moved during a max inhale and max exhale

Residual Volume

The amount of air left in the lungs that cannot be exhaled. It isn’t static and is still constantly getting exchanged

Lung volumes and growth

Lung volume grows by 28 times to a max of 5.5L age 25.

Minute ventilation (Ve)

The volume of air being exhaled per minute

Minute ventilation equation

Ve(1min^-1) =60/hrs Vt(1breath^-1) X Bf(breaths min^-1)

Breathing frequency

Bf

Ve during exercise

Ve increase by Vt & Bf to maintain resting gas pressure

4 components of blood

1. Plasma

2. Platelets

3. Leucocytes (White Blood Cell)

4. Erythrocytes (Red Blood Cell)

Plasma

Fluid. Mixture of water & dissolved substances (55% blood volume)

Platelets

Assist in repair after injury. Major role in blood clotting. Fragments of cells (<1% blood volume)

Leucocytes (White Blood Cells)

Involved in immune protection against infection (<1% blood volume)

Erythrocytes (Red Blood Cell)

Carry oxygen from lungs to tissue and CO2 to lungs. % of blood cells = haenatocrit. (40-45% of blood volume)

Hemoglobin

Iron rich pigment in blood. Easily binds with O2 in high partial pressure. Diffuses O2 to organs in low pp.

Erythropoietin

Increases RBC creation and there for O2 capacity. Increase hemoglobin

Legal ways to increase erythropoietin

Training at high altitudes or wearing gas masks

Illegal ways to increase erythropoietin

Blood doping and injections

3 main blood vessels

1. Arteries

2. Capillaries

3. Veins

Arteries

Large diameter. Thick muscle walls. Transport O2 rich blood away from heart to tissues

Capillaries

Supplied by arterioles. Narrow & thin walls. Sites of exchange between blood and tissue

Veins

Deliver mostly deoxygenated blood to the heart. Less muscular and fibrous than arteries. Flexible & contain valves = no back flow

Cardiac Cycle

Heart is a 4-chambered double pump system. Left & right sides of heart in parallel simultaneously. Atrium receives blood from vein. Ventricles push blood to arteries

Atrium

Receive blood from a vein

Ventricles

Push blood out of the heart into an artery

Hepatic

Drain the liver

Mesenteric

Carry nutrient blood from intestines