Ya 👍 ia merujuk kepada sistem pencernaan.

Apa yang termasuk dalam sistem G.I.

Sistem gastrointestinal (GI) ialah keseluruhan saluran pencernaan, dari atas hingga ke bawah:

Mulut
Esofagus (salur makanan)
Perut
Usus kecil
Usus besar (kolon)
Rektum & dubur

Ia juga melibatkan organ sokongan seperti:

Hati
Pankreas
Pundi hempedu

Terjemahan Bahasa Melayu

PENGENALAN KEPADA SISTEM GASTROINTESTINAL (GI)

Hai, apa khabar.

Saya akan memberi pengenalan kepada saluran gastrousus, iaitu gut, GI tract, atau alimentary canal.

Saya ada satu senarai video pengenalan kepada sistem-sistem badan, dan mungkin saya akan tambah pengenalan kepada bahagian-bahagian tubuh juga, kerana anatomi boleh dipelajari melalui dua pendekatan ini. Ini bermaksud kita akan mengikuti saluran pencernaan dari mulut hingga ke dubur, menelusuri keseluruhan tiub ini.

Fokus utama adalah anatomi (Struktur), tetapi kita juga akan menyentuh sedikit tentang fungsi (Fisiologi = cara ia berfungsi), kerana struktur dan fungsi saling berkaitan. Kita akan bergerak sepanjang saluran ini dan di penghujung nanti, kita akan tambah sedikit tentang sistem saraf dan bekalan darah.

Ini hanyalah pengenalan, jadi tidak terlalu terperinci. Saya akan tinggalkan beberapa perkara, tetapi saya ada banyak video lain yang jauh lebih mendalam jika anda mahu maklumat lanjut.

SALURAN GASTROINTESTINAL SEBAGAI SATU TIUB

Saluran gastrointestinal bermula sejak peringkat embrio, sebagai satu tiub yang sangat ringkas — antara bentuk terawal yang terbentuk. Ia adalah satu tiub yang berjalan melalui tubuh kita.

Menariknya, bahagian dalam tiub ini dianggap sebagai permukaan luar yang berada di dalam tubuh kita. Ini adalah konsep penting dalam perubatan dan anatomi.

Saluran ini mempunyai beberapa lapisan:

Lapisan dalam dipanggil mukosa
Secara asasnya, ia adalah tiub berotot

Contohnya di esofagus:

Ada otot yang memanjang (longitudinal)
Ada otot yang melingkar (circular)

Kedua-dua lapisan otot ini menghasilkan peristalsis, iaitu gerakan menolak makanan sepanjang saluran yang panjangnya beberapa meter.

PERANAN BAKTERIA (MIKROBIOM)

Di dalam saluran ini terdapat berbilion-bilion bakteria, yang hidup dan membantu proses pencernaan.

Tujuan sistem GI ialah:

Makan dan minum
Memecahkan makanan kepada molekul kecil
Melarutkan molekul tersebut
Menyerapnya melalui mukosa ke dalam darah

Apabila nutrien masuk ke dalam darah, barulah ia benar-benar menjadi sebahagian daripada tubuh kita.

Makanan yang tidak dicerna dan tidak diserap akan terus bergerak sepanjang saluran GI dan akhirnya dikeluarkan melalui dubur.

Selain itu, bahan buangan daripada badan (contohnya komponen hempedu) juga disalurkan ke dalam GI untuk disingkirkan. Inilah yang memberi warna coklat pada najis.

MULUT & PERMULAAN PENCERNAAN

Pencernaan bermula di rongga mulut:

Gigi memecahkan makanan
Lidah menggerakkan makanan
Kelenjar air liur mengeluarkan air liur yang mengandungi enzim

Deria rasa dan bau sangat penting kerana ia merangsang keinginan untuk makan dan membantu kita mengenal makanan yang sesuai.

Makanan yang telah dikunyah membentuk bolus, kemudian ditolak ke belakang mulut menuju ke faring, dan proses menelan berlaku.

ESOFAGUS & PERUT

Makanan dan air perlu melalui laluan yang sama dengan udara, sebab itu tersedak boleh berlaku.

Esofagus ialah tiub yang menghubungkan mulut dengan perut. Ia:

Biasanya tertutup
Terbuka apabila makanan masuk
Menggunakan peristalsis (bukan graviti)

Oleh itu, kita boleh makan walaupun dalam keadaan terbalik atau tanpa graviti.

Perut pula ialah:

Kantung berotot yang boleh mengembang
Tempat penyimpanan sementara makanan
Tempat pencernaan mekanikal dan kimia

Perut menghasilkan asid hidroklorik (HCl) untuk:

Mengaktifkan enzim pepsin
Memecahkan protein

Perut juga dilapisi mukus untuk melindungi dindingnya daripada asid.

USUS KECIL: DUODENUM, JEJUNUM, ILEUM

Perut melepaskan sedikit demi sedikit kandungannya (chyme) ke dalam duodenum.

Duodenum:

Bahagian pertama usus kecil
Menerima enzim dari pankreas
Menerima hempedu dari hati & pundi hempedu
Hempedu membantu mencerna lemak

Jejunum:

Tempat utama penyerapan nutrien
Mempunyai lipatan, vilus dan mikrovili untuk meningkatkan luas permukaan

Ileum:

Menyerap vitamin B12
Menyerap semula garam hempedu

USUS BESAR & NAJIS

Ileum bersambung ke usus besar melalui injap ileosekal.

Bahagian usus besar:

Sekum & apendiks
Kolon menaik
Kolon melintang
Kolon menurun
Kolon sigmoid
Rektum
Saluran dubur

Fungsi utama usus besar:

Menyerap air dan garam
Membentuk najis
Menyimpan najis sebelum dikeluarkan

Rektum mempunyai reseptor regangan yang memberi isyarat apabila perlu membuang air besar.

SISTEM SARAF & “OTAK USUS”

Saluran GI mempunyai sistem saraf enterik, sering digelar “otak kedua”:

Mengandungi kira-kira 500 juta neuron
Boleh berfungsi sendiri walaupun tanpa arahan otak

Ia dikawal oleh:

Sistem saraf parasimpatetik (rehat & cerna)
Sistem saraf simpatetik
Saraf vagus
Hormon pencernaan

BEKALAN DARAH

Saluran GI menerima bekalan darah terus dari aorta melalui:

Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery

Arteri ini berkait dengan pembahagian embrio:

Foregut
Midgut
Hindgut

KESIMPULAN

Saluran gastrointestinal ialah:

Satu tiub sepanjang kira-kira 7 meter
Permukaan luar yang berada di dalam tubuh
Berfungsi untuk mencerna, menyerap, dan menyingkirkan bahan

Setiap bahagian mempunyai struktur yang hampir sama, tetapi fungsi yang berbeza.

Ini hanyalah gambaran keseluruhan.

Jika anda mahu maklumat lebih mendalam, terdapat banyak video khusus mengenai topik ini.

Semoga ini bermanfaat dan menarik.

Jumpa lagi minggu hadapan.

ENGLISH VERSION

Introduction to the Gastrointestinal (GI) Tract

1. Introduction & Scope

Hi how are you doing
I'm going to give an introduction to the gastrointestinal tract, the gut, the GI tract, the alimentary canal.

I've got a bit of a playlist of introductions to systems and I'll probably add introductions to regions of the body because those are two ways you can approach anatomy.

That means we're going to work our way from mouth to anus. We're going to follow the tube all the way through.

Mostly focus on the anatomy. We're always going to talk a little bit about function because structure and function are related.

We'll work our way along the tube and add on a bit of nervous system and a bit of blood supply at the end.

It's not going to be in massive detail because this is an introduction, so I'm going to leave things out. But you'll find I have plenty of other videos of far too much detail if you'd like more.

2. The GI Tract as a Tube

So the gastrointestinal tract starts up here.

It starts in the embryo as a very simple tube. It's one of the first shapes to form. It's a tube that runs through us.

In that respect, the inside of the tube is an external surface inside of us, which is an important idea medically, clinically, anatomically.

It has a number of layers. It has a mucosa on the inside, does various things, but we can think of it as a muscular tube.

3. Muscle Layers & Peristalsis

There’s the esophagus there and two of the layers are muscle.

Some of the muscle is running longitudinally along the length of the tube and some of the muscle is running in a circular fashion around the tube.

Together, those use peristalsis to push the contents, the stuff that you eat, along that tube which is several meters in length.

The circular muscle squeezes the contents of the tube, and then the longitudinal muscle makes it shorter, pushing the contents along.

4. Gut Bacteria & Digestion

Inside that external surface within us, we find many, many, many bacteria.

The bacteria are living in there and helping us with our digestive processes.

The purpose of the gastrointestinal tract is to eat food and drink, break that down to molecules, solubilize those molecules, and take those molecules across the mucosa into the blood.

Once it's in the blood, it's in our body properly and then we can make use of it.

Food that is not digested is not absorbed and continues through the GI tract and is excreted through the anus.

Waste products produced by the body also get put into the gastrointestinal tract to be removed.

Bile from the gallbladder is very green and contains components being excreted, which gives feces their characteristic brown color.

5. Oral Cavity

The start of the gastrointestinal tract is the oral cavity.

We find teeth, a tongue, muscles of mastication, and salivary glands.

Digestion starts when we put food in our mouths. We break it down by chewing, and saliva starts enzymatic digestion.

The tongue moves food around to help with chewing. Taste and smell are important in wanting to eat and knowing food is good to eat.

Once food is broken down, we form a bolus and push it toward the pharynx, and swallowing occurs.

6. Pharynx & Swallowing

We put food, water, and air through the same passageway, which can be risky if food goes the wrong way.

Ideally, food passes into the pharynx and then into the esophagus.

7. Esophagus

The esophagus is posterior to the airway and runs against the vertebral bodies.

It connects the oral cavity with the stomach.

It does not rely on gravity; peristalsis moves food.

The esophagus passes through the thorax and through the diaphragm via a special opening.

8. Stomach

The stomach is a muscular, expandable bag that can store a whole meal.

It has layers of muscle running in different directions and a strong pyloric sphincter that keeps it tightly closed.

Food is churned, enzymes are added, and both mechanical and enzymatic digestion occur.

The stomach produces acid to break down proteins.

Pepsin is secreted in an inactive form and activated by hydrochloric acid.

The stomach is lined with mucus to protect it.

It releases small amounts of chyme into the duodenum.

9. Duodenum

The duodenum is the first part of the small bowel.

It forms a C-shape around the pancreas.

It is adapted to cope with stomach acid.

It receives pancreatic enzymes and bile from the liver and gallbladder.

Bile emulsifies fats and contains waste products.

10. Jejunum

The jejunum is where most absorption of nutrients occurs.

We see circular folds, villi, and microvilli, massively increasing surface area.

It is about two and a half meters long.

11. Ileum

The ileum is about three meters long.

It absorbs bile salts and vitamin B12.

Digestion and absorption continue as food passes through.

12. Large Intestine

The ileocecal valve ensures contents pass into the large bowel and not backward.

The cecum is the start of the large bowel, and this is where the appendix is found.

13. Appendix & Gut Bacteria

Bacteria exist throughout the gut.

During gastrointestinal illness, bacteria may be flushed out.

The appendix may retain good bacteria, allowing faster repopulation of the gut microbiome after illness.

14. Colon Sections

Ascending colon (fixed)
Hepatic flexure
Transverse colon (mobile)
Splenic flexure
Descending colon (fixed)
Sigmoid colon
Rectum

15. Rectum & Anal Canal

The rectum stores feces and stretch receptors signal when it should be emptied.

The anal canal has mechanisms to prevent emptying at inappropriate times.

There are smooth muscle sphincters (involuntary) and skeletal muscle sphincters (voluntary).

16. Nervous System Control

The GI tract has its own brain — the enteric nervous system — with about half a billion neurons.

It regulates digestion even without brain input.

Parasympathetic (vagus nerve) supports rest and digest.
Sympathetic nerves regulate blood flow and muscle activity.

Sensory fibers carry information back to the brain.

17. Hormonal Control

Hormones regulate digestive processes, switching them on and off depending on food presence.

18. Blood Supply

The aorta runs next to the GI tract.

Three major anterior branches:

Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery

These relate to embryological foregut, midgut, and hindgut.

19. Conclusion

The gastrointestinal tract is the alimentary canal — a tube that runs through us.

It is an external surface inside the body where substances are broken down, absorbed, and eliminated.

Each section has similar layers but different functions.

It is about seven meters long and works as a coordinated system.

Apa itu G.I ?