Human nutrition 1. There are six kinds of nutrients needed by human body: sugar, fat, protein, water, inorganic salts and vitamins.
Energy substance:
Sugar: the most important energy-supplying substance in human daily activities, and it is also a component of cells.
Fat: generally speaking, it is stored in the body as a spare energy substance; Heat preservation; The energy released per unit mass is the most.
Protein: the basic substance that constitutes human cells and participates in the repair and renewal of damaged cells; Provide energy for human physiological activities.
Non-energy substances:
Water: About 60%-70% of body weight. It is the main component of cells, and all kinds of physiological activities of human body are inseparable from water. Water is the most needed nutrient for human body.
2. The role of several inorganic salts:
3. The role of vitamins:
Composition of digestive tract of digestive system:
Oral cavity: teeth chew food; Tongue stirs food; Salivary glands secrete saliva to help digest starch.
Pharyngeal: The common passage of food and gas (the intersection of digestive tract and respiratory tract).
Esophagus: It can wriggle and push food into the stomach.
Stomach: (1) stomach peristalsis, so that food and gastric juice are fully mixed; (2) Gastric glands secrete gastric juice, which is digested by protein.
Small intestine: (1) The initial part is called duodenum, from which bile secreted by the liver and pancreatic juice secreted by the pancreas flow into the small intestine.
(2) Intestinal glands secrete intestinal juice (containing enzymes that digest sugar, protein and fat).
(3) The main place where food and digestive juice are fully mixed, digested and absorbed by peristalsis.
Large intestine: through peristalsis, food residues are pushed to the anus.
Anal: feces are discharged from it.
Human respiration 1. The respiratory system consists of respiratory tract and lungs.
2. Respiratory tract includes nose, pharynx, larynx, trachea and bronchus.
3. The function of respiratory tract is: ① the structure to ensure the smooth flow of gas; ② The inhaled gas can be treated to make the gas reaching the lungs warm, moist and clean.
4. The ability of respiratory tract to deal with air is limited. So we should keep the air in the environment fresh.
5. The pharynx is both a digestive organ and a respiratory organ.
The basic way of neuromodulation is 1. There are two major regulation systems in human body: ① regulation of nervous system (neuromodulation).
② Regulation of endocrine system (hormone regulation)
2. The basic way of nerve regulation is: reflex (the regular response of the nervous system to stimulation).
3. The structural basis of reflection is called reflex arc.
4. Reflex arc consists of five parts (must be complete): receptor, afferent nerve, nerve center, efferent nerve and effector.
5. Types of reflection: unconditional reflection and conditional reflection.
Structure and function of eyeball cornea: colorless, transparent and light-transmitting.
Scleral: white and tough, protecting the inside of eyeball (white part of eyeball).
Iris: Pigment (determines the color of human eyes, such as black, brown, blue, etc. ), and the central hole is the pupil.
Choroid: There are blood vessels (providing nutrition for the eyeball) and pigment cells (shading, forming a "dark room" inside the eyeball).
Pupil: the passage through which light enters, the size of which can be adjusted. Pupils shrink in strong light and expand in dark light.
Retina: There are a large number of photosensitive cells on the surface, which can feel the stimulation of light and form an object image.
Lens: A biconvex lens with adjustable curvature, which refracts light and enables the eyes to see objects at different distances.
Ciliary body: adjust the curvature of the lens.
Vitreous body: a transparent colloidal substance that supports the wall of the eye and refracts light.
Blood 1. Blood consists of plasma and blood cells. Blood has the functions of transportation, defense and protection, and is called mobile tissue.
2. After blood stratification, the upper yellowish translucent liquid is plasma. The lower layer is red blood cells, red; White blood cells and platelets are thin and white at the junction of these two layers.
3. The main function of plasma is to carry blood cells and transport substances needed to maintain human life activities and wastes generated in the body.
4. Blood cells include red blood cells, white blood cells and platelets.
5. Mature red blood cells have no nucleus, the largest number, and are rich in hemoglobin. It has the function of transporting oxygen.
6. White blood cells have nuclei, which are larger than red blood cells, but fewer in number. It can devour germs and play a defense and protection role for human body.
7. Platelets are the smallest blood cells, with no nucleus and irregular shape. It has the functions of stopping bleeding and accelerating blood coagulation.