Anatomy and Physiology 1

Heart

Heart

Delivers oxygen

Delivers heat to the surface of the skin

Removes the waste products in the body

Route taken by blood

RVAVAVAL

Chambers of the heart

Right atrium, right ventricle, left ventricle left atrium separated by the septum

Size and strength of chambers

Atriums have thin muscle walls

Ventricles have thick walls

Left side of the heart is larger

Name and location of valves

Bicuspid separates left atrium and ventricle

Tricuspid separates right atrium and ventricle

Semi lunar valves separate ventricles and arteries

Chordae Tendineae

Strong fibrous strings that attach heart muscles to the valves. They serve to anchor the valves and not let them close

Cardiac Conduction system

A group of specialised cells located in the wall of the heart which send electrical impulses to the cardiac muscle, causing it to contract.

SAN

Sino atrial node

Begins the wave of excitation

Myogenic

Capacity of the heart to generate its own impulses

What is the impulse described as

Wave of excitation

AVN

Atrio ventricular node

Delays the wave of excitation to limit the increase of the Heart rate

Systole and diastole

Heart pumping and the heart filling respectively

What follows the AVN

Bundles of HIS, splitting into bundle branches

What follows bundle of HIS

Purkinje fibres, these spread the impulses around the ventricles and cause them to contract

Neural Control system

Central nervous system

Peripheral nervous system

Autonomic nervous system

CNS

Brain

Retina

Spinal cord

Command centre of the body

Peripheral nervous system

Nerves that connect the CNS to the arms and legs

Autonomic nervous system

Nerves that connect the CNS to organs

What is the autonomic nervous system split into

Sympathetic and Parasympathetic

Sympathetic

A part of the nervous system that speed up heart rate and prepares the body for exercise

Parasympathetic

Decreases heart rate and returns the body to a resting state after exercise

Medulla Oblongata

Cardiac Control Centre

Responsible for autonomic nervous functions

What is the medulla oblongata stimulated by

Chemoreceptors

Baroreceptors

Proprioceptors

Chemoreceptors

Detect changes in the acidity and chemicals in the bloodstream

Increase in CO2 = increase in heart rate

Baroreceptors

Detect changes in blood pressure

Increase in blood pressure= decrease in HR

Proprioceptors

Detect changes in muscle movement and tension

Increase muscle movement = Increases HR

Hormonal Control System

Adrenaline is released from the adrenal glands and mimicks the sympathetic nervous system increasing heart rate before exercise

Stroke volume

The volume of blood pumped by the ventricles for each contraction

Ejection fraction

The percentage of blood pumped out by the left ventricles per beat

cardiac output

stroke volume x heart rate

Venous return

Amount of blood returning to the lungs via the veins

Starlings law

Increased venous return, increased diastolic filling, cardiac muscle is stretched, more force of contraction, increased ejection fraction

Myocardium

Cardiac tissue

Cardiac hypertrophy

The thickening of the muscular wall of the heart so it becomes stronger

Bradycardia

A decrease in resting heart rate below 60bpm

Coronary Heart Disease

Coronary arteries are blocked and lumen is narrow reducing blood flow

Atherosclerosis/ atheroma

The process of fatty build ups being deposited in the vessels. Atheroma is the fatty deposits

Angina

Chest pain when the coronary arteries are blocked enough to cause pain

Blood Pressure

The force exerted by the blood on the walls of the blood vessels

Cholesterol (LDL)

Low density lipoproteins

Transports cholesterol to the blood vessels. Considered the bad ones as linked to heart disease

Cholesterol (HDL)

High density lipoproteins

Transport atheroma back to the liver where it is broken down. Considered the good ones as they lower the risk of CHD

Ishaemic stroke

The most common. Occur when a blood clot stops blood supply

Haemorrhagic Strokes

occur when a weakened blood vessels supplying the brain bursts

Cardiovascular drift

Heart rate increases

Stroke volume decreases

Fluid is lost as sweat

Reduced plasma volume

Reduced venous return

Cardiac output also increases due to more energy needed to cool the body

5 different types of blood vessels

Arteries

Arteriols

Capillaries

Venules

Veins

Veins

Thinner muscle/ elastic tissue

Blood is at low pressure

Valves

Wider lumen

Arteries

Thick muscle and elastic tissue

Small lumen

High blood pressure as they carry blood away from the heart

Capillaries

One cells thick

Short diffusion path for oxygen and Co2

Very low blood pressure

Systemic blood pressure

Pressure of the oxygenated blood travelling to the body

The pressure in the arteries when the heart is contracting

Diastolic blood pressure

The pressure of the deoxygenated blood travelling from the heart to the lungs

The pressure in the arteries when the ventricles are relaxing

Where is blood pressure measured from

The brachial artery in the upper arm

What is a healthy blood pressure

120/80

Three mechanisms for venous return

Skeletal muscle pump

Respiratory pump

Pocket valves

Skeletal muscle pump

The muscles contracting and changing shape resulting in veins to change shape and squeeze the blood back to the heart

Respiratory pump

The pressure changes in the thoracic and abdominal cavities during breathing and will therefore compress the nearby veins and push blood back to the heart

Pocket valves

These valves prevent the back flow of blood in the veins

Equation for blood pressure

Blood flow x resistance

What is venous return determined by

Pressure gradient

Mean systemic pressure

The mean pressure that exists in the circulatory system when the heart has had a chance to evenly redistribute blood to all vessels and organs

Peripheral veins

Lead deoxygenated blood from the capillaries back to the heart

Vascular resistance

The resistance that must be overcome for the blood to be pushed around the circulatory system

Haemoglobin

An iron-containing pigment found in red blood cells, which combines with oxygen to form oxyhaemoglobin

Myoglobin

Often known as muscles haemoglobin

Stores the oxygen in the muscles to be used during longer activities

Mitochondria

Site for aerobic respirations and is the powerhouse of the cell

High affinity for oxygen

Need lots of oxygen to operate

What is the name for the translation of the curve in the positive x direction

BOHR shift

What factors impact the BOHR shift

Increased temperature

Increased partial pressure of CO2

Lower pH (increased acidity)

What is the redirecting of blood to the areas that need it called?

Vascular shunt mechanism

What happens to the blood during vigorous exercise as a result of a vascular shunt?

Blood is distributed away from digestive organs and travels to the working muscles.

Pre capillary sphincters

Rings of tissue at the start of the blood vessel. When contracting, they block of the proceeding vessel and there is limited blood flow to the areas that vessel supplies.When they contract blood flow is blocked.

Vasodilations and Vasoconstriction

Dilation- the widening of the lumen to allow more blood flow. This also pushes the vessel closer to the surface to allow for heat to leave the body

Constriction- Vessels decrease lumen diameter and go deeper into the skin resulting in a conservation of heat

Why is blood distribution important? (4 things)

Increase supply of oxygen

Remove lactic acid and other waste products

Regulation of body temperature

Direct more blood to the heart

Atrio-venous difference

The difference between the content of oxygen of the arterial blood arriving at the muscles and the venous blood leaving the muscles

At rest, what is the AVO2 like

Low as not much oxygen is required at the muscles

What is the equation for venous pressure

Venous pressure - Right atrial pressure /Total peripheral vascular resistance

The sections of vertabrae

Cervical, thoracic, lumbar, sacrum, coccyx

Bones in the pelvis

Iliac crest

Ilium

Pubis

ischium

Cervical vertabrae

7 bones

Provides support for the weight of the head and surrounds and protects the spinal cord

Thoracic vertabrae

12 vertabrae

Provides attachment point for multiple muscles

Lumbar vertabrae

5 vertabrae

Provides stability for the spinal column and back

Sacrum vertabrae

5 vertabrae

Is fused to the coccyx and is responsible for strengthening the pelvis

Coccyx

4 vertabrae

Fused to sacrum and provides weight bearing support when seated also multiple insertion point for muscles and ligament

5 types of bones

Long

Short

Irregular

Flat

Sesamoid

Long bone

Longer than it is wide

Femur, humerus, tibia, fibula

Shaft called diaphysis and ends called epiphysis

Short bone

Cube shaped consisting of cancellous bone surrounded by a layer of compact bone

Carpals, Tarsals, Wrists

Fine or small movements, shock absorption, weight bearing

Flat bone

Thin, flattened and slightly curved, with a large surface area.

Sternum, Cranium

Irregular bone

Mostly protect the spinal cord and allow small amounts of movement

Vertabrae

Sesamoid bones

Have a specialised function

Protection and reduction of friction at a joint

Patella

Ligaments

Strong fibrous tissue

Stabilise the joint, attach bone to bone, prevent any unwanted movement

Fibrous joint

Fixed position

Protects vital organs

Bones overlap and interlock

Cartilaginous joint

Slightly moveable

Bones are separated by fibrocartilage which when compressed, will move bones

Synovial joint

Freely moving

High level of mobility at the joint

Most of e body’s joints are synovial

Functions of the skeletal system (PASS and MOVE)

Protection, Attachment, Blood cell production, Store of minerals, Movement

Neuromuscular system

Nervous system and muscular system work together to allow movement

Three different muscle fibres

1, 2a, 2x

Type 1 muscle fibre

Small and red

Slow force of contraction and speed

Aerobics

High fatigue resistance

High mitochondria and high slow release sugars

Type 2a fibres

Moderate and red

Medium force of contraction and speed

Aerobics

High fatigue resistance

Type 2x fibres

Large and white

High force of contraction and speed

Weight lifting and sprinting

High glucose

Low fatigue resistanace

Motor Unit

A motor neurone and its muscle fibres

Motor neurones

Nerve cells which transmit the brains instructions as electrical impulses to the muscles