Cardiac Cycle and Heart Sounds

• Cardiac Cycle refers to one complete heartbeat.
• The heart is actually 2 pumps situated side by side, so a complete cycle consists of contractions of both atria and both ventricles.
• The average resting heart rate is approximately 75 beats per minute
• Resting heart rate will vary with degree of physical conditioning as well as with disease states
• The familiar “lub-dub” associated with the function of the heart are known as heart sounds.
• The heart sounds are made by the heart valves snapping closed under contractile pressure.

• The “lub” is caused by the closure of the AV valves
• The “dub” is caused by the closure of the semi-lunar valve.
• Cardiac output (CO) is the amount of blood pumped out of each side of the heart ( meaning the ventricles ) in one minute
• The value of CO is calculated as the product of the Heart Rate ( HR) multiplied by the Stroke Volume (SV)
• SV generally increases as the force of the ventricular contractions increases.
• CO = HR  x SV
• CO = 75 beats per min x 70mls per beat
• CO = 5250 ml/min
• Generally speaking, blood starting in the heart should complete a circuit of the body and arrive back in the heart in one minute.
• According to Starling’s Law of the heart, stroke volume is influenced by the amount of stretching force applied to the muscle cells of the heart.
• The more the cells are stretched, the great the contraction will be

Starling’s Law of the Heart

• A healthy, efficient heart only pumps about 60% of the volume of blood in the ventricles.
• Venous return is critical to the amount of stretching the heart undergoes.
• If one side of the heart begins to pump more blood than the other, the increase in venous return to the opposite ventricle will force it to pump a larger volume of blood.
• This helps prevent back ups and increased pressures in the system.
• Anything that increases the volume or speed of venous return will also increase the SV and CO.
• The squeezing actions of skeletal muscles on veins also plays a major role in increasing venous return.

Regulation of Heart Rate

• Coronary contraction does not depend on stimulus from the nervous system, because the heart has it’s own intrinsic pacemakers ( SA and AV nodes)
• HOWEVER—heart rate can be temporarily influenced by stimulus from the autonomic nerves.

• Sympathetic nerves can act to increase or decrease the heart by stimulating the SA or AV nodes.
• Parasympathetic nerves act to decrease the heart rate
• Being excited or startled can cause a rapid increase in heart rate.
• Heart rate can also be influenced by hormones
• Epinephrine and Thyroxine mimic the effects of the sympathetic nerves.
• Ion concentrations also has a rofound influence on the heart.
• Decreased Ca+ will depress the heart rate
• Excessive Ca+ will cause prolonged contractions, and possibly stop the heart from beating.

CHF and Blood Vessels

• When the pumping efficiency of the heart is depressed so that circulation is inadequate to meet tissues needs, congestive heart failure (CHF) results.
• CHF is usually a progressive condition, and in most cases reflects diminished coronary circulation by coronary atherosclerosis
• Each side of the heart can fail independently
• If the left side fails, pulmonary congestion will occur.
• The right side continues to pump blood, but the left side is unable to push oxygenated blood into systemic circulation
• The blood vessels of the lungs become swollen with blood, and the increased pressure forces fluids to leak from circulation and into the lung tissue, resulting in pulmonary edema.
• Suffocation will result if this condition is untreated.
• If the right heart fails, blood is not moved out of the systemic circulation, and peripheral congestion will occur.
• This results in edema in distal parts of the body, such as the feet, ankles and hands.
• Failure of one side of the heart places increased strain on the opposite side of the heart—eventually leading to whole heart failure

Blood Vessels

• Blood circulates through the body within the vasculature.
• In decreasing size order, vessels carrying blood away from the heart are, arteries, arterioles, capillary beds.
• In increasing size order, vessels carrying blood back towards the heart from the capillary beds are, venules, and veins

• The walls of most blood vessels consist of three layers called tunics.
• The innermost layer is called the tunica intima.
• Tunica intima consists of a thin layer of closely fitted endothelial cells.
• It is very smooth, to allow for smooth flow of blood
• The tunica media is the middle layer of tissue, and is primarily smooth muscle tissue and elastic connective tissue.
• This smooth muscle is controlled by the sympathetic nervous system, which changes the diameter of the blood vessels
• The tunica externa is the outer-most layer, and is mostly fibrous connective tissue that supports and protects the vessel.
• The walls of arteries are usually thicker than those  of the veins.
• Veins are subject to less pressure than ateries, but move blood against gravity.
• Veins contain one way valves to prevent backflow of blood

Hormone Functions

•          ACTH (adrenocorticotropic hormone)

•         Regulates the activity of the cortex of the adrenal gland

•          TSH (thyroid stimulating hormone)

•          Stimulates production and release of thyroid hormone

•          GH (growth hormone)

•          Stimulates growth of bones, cartilage, muscle

•          Timing and amount released determines body size

•          PRL (prolactin)

•          Stimulates breast development

•          Promotes and maintains lactation after childbirth

•          FSH (follicle stimulating hormone)

•          Causes formation of ovarian follicles and stimulates them to produce estrogen

•          Stimulates sperm development in men

•          LH (luteinizing hormone)

•          Initiates ovulation, maintains corpus luteum

•          Regulates testosterone production in males

•          ADH (antidiuretic hormone)

•          Reduces urine output by increasing water reabsorption in the kidney

•          Plays small role in blood pressure regulation

•          Oxytocin

•          Causes uterine contractions in labor

•          Causes milk let down in lactating mothers

•          Thyroid Hormone

•          Regulates metabolic rate of the entire body

•          Important in development of the nervous system

•          Calcitonin

•          Decreases bone reabsorption, lowering serum calcium levels

•          PTH (parathyroid hormone)

•          Increases serum calcium

•          Decreases serum phosphorus

•          Insulin

•          Released in response to high blood sugar

•          Increases cellular absorption of glucose

•          Increases rate of lipogenesis and formation of glycogen in the liver

•          Glucagon

•          Released in response to low blood sugar

•          Increases rate of gluconeogenesis (formation of sugar from fat and protein)

•          Increases lipolysis and glycogenolysis

•          Epinephrine & Norepinephrine

•          Fight or flight response

•          Increase heart rate, increase skeletal muscle blood flow, decrease skin blood flow

•          Glucocorticoids (Cortisone)

•          Released in response to stress

•          Increases formation of glucose from protein and fat breakdown

•          Decreases inflammation

•          Aldosterone

•          Increases blood volume by causing kidneys to retain sodium (where sodium    goes water goes too) in exchange for potassium

•          Increased blood volume will increase blood pressure

•          Androgens

•          Initiates pubertal changes

•          Precursors to estrogen in postmenopausal women

•          Melatonin

•          Involved in circadian rhythms

•          Day ¯ melatonin, Night ­ melatonin

•          Produces sleepiness

•          Erythropoietin

•          Stimulates RBC production

•          Calcitriol

•          Stimulates calcium and phosphate absorption

•          Stimulates calcium release from bone

•          Inhibits PTH secretion

Diabetes

•          Type 1: Insulin Dependent Diabetes

•          AKA: juvenile diabetes

•          Caused by a lack of insulin

•          Autoimmune disorder

•          Immune system destroys beta cells in the pancreas

•          Type 2: Non-Insulin Dependent

•          Caused by an insensitivity of cells to insulin.

•          Diabetes mellitus marked by hyperglycemia

•          ­ urine production (polyuria)

•          ­ thirst (polydipsia)

•          ­ eating (polyphagia)

Diagnosing Diabetes Mellitus

•          Normal blood glucose levels: 70-100 mg/dl

•          Diabetes mellitus:

•          A fasting glucose level above 140 mg/dl on two separate occasions, or

•          A blood sugar over 200 mg/dl 2 hours after oral glucose tolerance test with    75gm of glucose

•          Impaired Glucose Tolerance (Pre-Diabetes)

•          A fasting glucose level between 100-126 mg/dl on two separate occasions,      or

•          A blood sugar between 140-200 mg/dl 2 hours after oral glucose tolerance      test with 75gm of glucose

Tenaga / Kadar Metabolisme Tubuh

Keupayaan untuk bekerja

• Tenaga kimia yang terdapat dalam badan makanan kerana wujudnya ikatan kimia di dalam nutrien.
• Dikaitkan dengan keperluan tubuh manusia untuk hidup dan bekerja.
• Tenaga matahari:  Sumber asas semua tenaga yang boleh ditukarkan kepada bentuk kimia dalam makanan.

Tenaga Penting dalam Tubuh

• Tenaga Kinetik: Tenaga yang dibekalkan oleh sebatian ikatan bertenaga tinggi seperti ATP, ADP, dll.
• Tenaga berpotensi: Tenaga yang tidak aktif disimpan di dalam badan dalam bentuk glikogen dan yang terdapat dalam makanan.

Pengukuran Tenaga

• Kalori: Jumlah tenaga haba yang diperlukan untuk menaikkan suhu satu gram air sebanyak satu darjah celsius.
• Kilokalori (Kcal): Jumlah haba yang diperlukan untuk meningkatkan suhu 1 kg. air sebanyak sebanyak 1 darjah celsius.Unit metrik yang digunakan ialah kilojoule (KJ) 1 Kilokalori (Kcal) =   4.184 KJ

Pengukuran Nilai Tenaga dalam Makanan

• Dengan menggunakan alat kalorimeter
• Jumlah tenaga yang dihasilkan oleh setiap sampel protein, lemak dan karbohidrat:

                1 gm. Karbohidrat                =             4 kcal

                1 gm. Lemak                        =             9 kcal

                1 gm. Protein                        =             4 kcal

                1 gm. Alkohol                       =             7 kcal

Contoh Pengiraan 1

Berapakah nilai tenaga yang dalam satu gelas susu beratnya 244g ? Jika dalam susu 100g susu mengandungi:

4.9g  CHO; 3.5g protein; 3.7g lemak; 0.6 mineral dan 1.2g vitamin

• CHO                         =             244/100 x 4.9g x 4kcal      =   47.8 kcal 
• Protein                       =            244/100 x 3.5g x 4kcal     =   34.2 kcal 
• Lemak                       =             244/100 x 3.7g x 9kcal     =   81.3 kcal
• Jumlah nilai tenaga                                                        =  163.3 kcal

Contoh pengiraan 2

Diet mengandungi 2200 kcal dan mengandungi 210g CHO, dan 120g lemak, kira: 

• Berapakah jumlah g protein dalam sajian?
• Kira peratus setiap nutrien [CHO, protein dan lemak] dalam sajian?

Jumlah g protein 

CHO membekal         =  210 x 4 kcal                      =    840 kcal

Lemak membekal      =  120 x 9 kcal                      =  1080 kcal

Protein                     =  2200 – (1080 + 840)            =     280 kcal

Jumlah g protein     =  280/4                               =    70 g

Peratus CHO, Protein dan Lemak

Peratus CHO             =  840/2200  x  100               =    38.2%

Peratus Lemak          =  1080/2200 x  100              =    49.1%

Peratus Protein        =   280/2200  x  100            =    12.7%

Input Tenaga

Tenaga/kilokalori yang terdapat dalam makanan

Output Tenaga

Tenaga yang diperlukan @ digunakan oleh tubuh untuk beberapa perkara:

• Kadar Metabolisme Asas [Basal Energy Rate]
• Aktiviti Fizikal
• Pertumbuhan
• Tindakan Spesifik Dinamik Makanan 

Bilakah Kadar Metabolisme Asas diukur?

• Selepas 12 – 18 jam mengambil makanan terakhir.
• Seseorang dalam keadaan rehat.
• Dalam bilik yang sesuai, suhu selesa.
• Kebiasaan diukur selepas bangun tidur waktu pagi. 

Pengukuran Penggunaan tenaga

• Jumlah tenaga yang dijana @ digunakan oleh tubuh dapat diukur secara langsung @ tidak langsung.
• Kilorimetri Langsung
• Individu diletakkan di dalam kilokalorimeter /bilik khas
• Kaedah sangat mahal. Cuma beberapa unit terdapat di seluruh dunia
• Di Malaysia hanya satu terdapat di Universiti Hospital.

Kilorimetri Tak Langsung

• Kaedah yang lebih mudah
• Diukur dengan menentukan penggunaan oksigen dan pengeluaran karbon dioksida pada masa tertentu  dengan menggunakan alat respirasi
• Dapat digunakan semasa individu berbaring rehat @ menjalankan berbagai aktiviti
• Pada setiap liter oksigen yang digunakan akan memerlukan 4.825 kilokalori tenaga.

Kadar Metabolisme Asas [KMA]
Basal Metabolisme Rate[BMR]

Kadar Metabolisme Asas

Jumlah tenaga yang diperlukan oleh tubuh untuk memiara/menjalankan proses-proses penting dalam tubuh - Kadar tubuh menggunakan tenaga untuk kekalkan fungsi penting untuk hidup.

Kadar Metabolisme Rehat (KMR) - Penggunaan tenaga pada keadaan yang sama kecuali selepas makan atau berlatih.

Kaedah mengira keperluan tenaga untuk KMA (Basal Metabolisme Rate). Menggunakan anggaran 1 kilokalori/minit

                =             60 m/jam X 24jam/hari

                =             1440 kilokalori/hari 

Alat Respiratori Bebedict-Roth (Penggunaan O2)

Ali mengambil 1.08 liter O2 dalam masa 6 minit. Kira berapa jumlah keperluan tenaga KMA dalam sehari ? [Piawai 1 liter O2 = 4.825 kcal]

               

                6 minit  Ali mengambil 1.08 liter oksigen

                1 jam (60 minit)                        =             1.08 x 60/6

                                                                =             10.8 liter Oksigen

                Sehari (24 jam)                         =             10.8 liter x 24 jam

                                                                =             259.2 liter Oksigen

                 KMA                                         =             259.2 x 4.825

                                                                =             1251 kkal.

Berasaskan Berat badan, Umur & Jantina :

Lelaki    

                < 50 tahun  =      1.0 kkal/kg X  BB/1 Jam

                > 50 tahun  =      0.9 kkal/kg  X BB/1 Jam

Wanita

                < 50 tahun  =      0.9 kkal/kg X  BB/1 Jam

                > 50 tahun  =      0.8 kkal/kg  X BB/1 Jam

Contoh:

Kira berapakah jumlah tenaga untuk KMA dalam sehari bagi mereka berikut?

En. Adam berumur 45 tahun mempunyai berat badan 65 kg

                                              Keperluan tenaga KMA      = 1 x 65 x 24 jam

                                                                                     =  1560 kcal

Cik Fatimah berumur 26 tahun mempunyai berat badan 46 kg.

                                              Keperluan tenaga KMA      = 0.9 x 46 x 24 jam

                                                                                     =  993.6 kcal

Latihan:

Kira berapakah jumlah tenaga untuk KMA dalam sehari bagi mereka berikut?

1. En. Ramlee berumur 45 tahun mempunyai berat badan 65 kg
2. Cik Fatimah berumur 25 tahun mempunyai berat badan 46 kg.
3. Pak Adam berumur 66 tahun mempunyai berat badan 63 kg
4. Mak Timah berumur 70 tahun mempunyai berat badan 81 kg.

Kaedah Pengiraan WHO

Gunakan Berat badan (dalam kg)

Wanita : 

Berat dalam Kg x 0.95 kcal x 24 jam

Lelaki :

Berat dalam Kg x 1.0 kcal x 24 jam

Contoh:

Aminah berumur 13 tahun dan berat badan 50 kg.

50kg x 0.95 kcal x 24 jam    =   1140 Kcal

Ramlee, berat badan 58 kg dan berumur 25 tahun

58kg x 1.0 kcal x 24 jam      =   1392 Kcal

Latihan: 

Kira berapakah jumlah tenaga untuk KMA dalam sehari bagi mereka mengikut kiraan WHO?

1. En. Yunus berumur 48 tahun mempunyai berat badan    73 kg 
2. Cik Rohani berumur 28 tahun mempunyai berat badan 53 kg.
3. Hamidah berumur 35 tahun mempunyai berat badan 62 kg 
4. Halim berumur 70 tahun mempunyai berat badan  74 kg.

Formula FAO/WHO untuk ukur  REE [Resting Energy Expenditure]

LELAKI
3 - 9	22.7 w + 495
10 - 17	17.5 w + 651
18 - 29	15.3 w + 679
30     - 60	11.6 w + 879
> 60	13.5 w + 487

WANITA
3 - 9	22.5 w + 499
10 - 17	12.2 w + 746
18 - 29	14.7 w + 496
30     - 60	8.7 w + 829
> 60	10.5 w + 596

Latihan:

Aminah  mempunyai berat badan 50 kg. , berumur 18 tahun .  Kirakan keperluan tenaga Aminah dalam sehari dengan menggunakan Formula REE ?

                =             14.7 w  +  496

                =             ( 14.7 x 50 )  +   496

                =             735  +   496

                =             1231 kcal/hari

Hamid mempunyai berat badan 78kg dan berumur 33 tahun.  Kirakan keperluan tenaga dengan Formula  REE?

               

Faktor-Faktor yang mempengaruhi Kadar Metabolisme Asas seseorang

Komposisi tubuh

• Kandungan tisu seseorang.
• Tisu tanpa lemak  (otot) : tinggi KMA
• Tisu berlemak sedikit tenaga untuk memiara tisu ini.
• Lelaki perlu KMA tinggi kerana mempunyai lebih tisu tanpa lemak.

 Keadaan Tubuh: Jalankan aktiviti Fizikal

•  2 lelaki sama umur, tinggi & berat badan
•  Jalankan tugas fizikal yang berbeza. Seorang buruh dan seorang akauntan
•  Buruh perlu banyak KMA berbanding akauntan kerana buruh mempunyai otot-otot terbentuk berbanding akauntan

Jantina

• Lelaki lebih tenaga KMA berbanding wanita
• Lelaki muda dewasa mempunyai 14% lemak daripada berat badan
• Wanita muda dewasa mempunyai 23%- 32% lemak daripada berat badan

Tidur

• Kurang tenaga KMA

Malnutrisi

• Tenaga KMA rendah

Tekanan mental

• Lebih tenaga bagi orang. yang mengalami masalah mental

Suhu Tubuh

• Kalau suhu tubuh tinggi KMA tinggi
• Setiap 1 darjah tambahan suhu boleh tingkatkan 13 kcal KMA badan

Suhu persekitaran

• suhu panas kita perlu KMA yang rendah
• suhu sejuk kadar KMA tinggi bagi panaskan badan

Kehamilan

• Tenaga KMA tinggi untuk menghamil bayi 300- 330 kcal lebh daripada wanita biasa
• Ibu menyusu KMA tinggi bagi proses mengeluarkan susu 500- 550 kcal lebih daripada wanita biasa

Umur

• Umur meningkat keperluan KMA menurun

Merokok

• lebih 10 peratus daripada orang tidak merokok

Soalan:
Norzalina  25 tahun, tinggi 1.63 m dan berat badan 65 kg.  Berikut adalah jumlah kalori yang dimakan iaitu karbohidrat 190g;  protein 120g dan  lemak 93g mengikut 24-hour dietary recallnya.

Dengan menggunakan data di atas kirakan:

                                (i)            jumlah kalori dan tunjukkan peratus karbohidrat, protein dan lemak ? 

                                (ii)           Peratus pengambilan makanan

Beri penjelasan tentang diet yang diamalkan oleh Norzalina mengikut perkiraan WHO menggunakan                                             (i) berat badan dan (ii) norma REE

(i)            Jumlah pengambilan kalori:

                a.            karbohidrat         =             190 X 4 kcal        =  760 kcal

                b.            protein               =             120 X 4 kcal        =  480kcal

                c.             lemak                =               93 X 9 kcal        =  837 kcal

                                                                          Jumlah            =  2077kcal

(ii)           Peratus pengambilan makanan

                a.            karbohidrat        =             760/2077 X 100  =  36.6 %

                b.            protein               =             480/2077 X 100  =  23.1 %

                c.             lemak                =             837 /2077 X 100 =  40.3%

i.              Berat badan dengan perkiraan WHO

                                =             0.95 kcal X kg (berat badan) X 24 jam

                                =             0.95 kcal X 65 kg  X  24 jam

                                 =           1482 kcal

 ii.             Berat badan berdasarkan Norm               

                                =             (14.7W)  + 496

                                =             (14.7 X 65 ) + 496

                                =             955.5 + 496

                                =             1451.5 kcal

Berdasarkan penjadualan Pemakanan Norzalina telah mengambil lebihan makanan:

Mengikut kiraan berat badan mengikut Formula WHO   

                                =             595 kcal [2077 – 1482]

Mengikut keperluan norm                     

                                =             525.9 kcal [2077 – 1551.1 ]