Introduction to Physiology PDF

Introduction for physiological What is homeostasis: 1) The body is organized into a functional unit. 2) Levels of organization include various structural components: ❖ Organism ❖ body systems ❖ organ ❖ tissue ❖ cell ❖ molecule ❖ atom What is fun...

Introduction for physiological What is homeostasis: 1) The body is organized into a functional unit. 2) Levels of organization include various structural components: ❖ Organism ❖ body systems ❖ organ ❖ tissue ❖ cell ❖ molecule ❖ atom What is function basic cells unit of life: 1) Obtain food and oxygen 2) Perform chemical reactions 3) Eliminate carbon dioxide and waste 4) Synthesize proteins and cell components 5) Control exchange of materials 6) Respond to environmental changes and reproduce What is the human body made of? 1) Circulatory 2) digestive 3) respiratory 4) urinary 5) skeletal muscular 6) integumentary 7) immune 8) nervous 9) endocrine 10) reproductive What is meant of ECF? ▪ Acts as a bridge between cells and their outside environment , How? 1) Exchanges of substances between intracellular fluid (ICF) and the external environment happen through extracellular fluid (ECF). 2) Water introduced into the body initially enters the ECF compartment. 3) Fluid leaves the body via the ECF. 4) The ECF mediates all fluid movement in and out of the body.  what is role Homeostasis in the body? 1) Homeostasis refers to the maintenance of a stable internal environment. 2) Body systems work together to achieve a dynamic steady state within this internal environment. , such as: ❖ Chemical composition ❖ Volume ❖ Temperature ❖ Osmolarity What is the method for Control of homeostasis? 1) Negative feedback 2) Positive feedback How can work the Negative feedback in the body? 1) Negative feedback counteracts changes to maintain homeostasis. 2) It causes a controlled variable to move opposite to the initial change. 3) The body is controlled by Negative feedback ❖ For example about Negative feedback: ▪ When the sugar level in the body rises "Daddy' ▪ When blood pressure rises or in case of low blood pressure How can work the Positive feedback in the body? 1) Positive feedback strengthens an initial change. 2) ) An output is improved as a controlled variable aligns with the initial change. 3) usually deleterious and dangerous ❖ For example about Positive feedback: batol ▪ It is only used in the case of childbirth. It causes contractions in the uterus, which leads to pushing the fetus out. * What is barriers to transport cell membrane? 1) Cell membranes are semi-permeable, allowing selective passage of substances. 2) They block most common biological compounds from crossing. How much total water inside and outside cell: 1) Extracellular (Outside cell) = 20% / 14L 2) Intracellular ( Inside cell ) = 40 % \ 28L 3) Body water = 60% /42L ▪ The ICF (intracellular fluid) and ECF (extracellular fluid) are separated by cell membranes. ▪ These membranes allow water to pass while regulating the movement of specific ions. ❖ Important, the largest percentage of water is present inside the cell ICF What is Ionic composition in the cells : 1) Cations: + charged ions 2) Anions: - charged ions In the ECF for Ionic composition: 1) The cation ratio is very high in ECF such as: Na+ but low ratio like K+ in the ECF but , Anions ratio is high like CI 2) what is Nutrients in the ECF: ❖ glucose, fatty acids, & amino acids, O2 3) what is wastes proudct in the ECF: ❖ CO2, Urea, uric acid, excess water, & ions. In the ICF for Ionic composition: 1) The cation ratio is very high in ICF such as: K+ but low ratio like Na+ in the ICF 2) What is Nutrients in the ICF: ❖ High concentrations of proteins. What is Passive Transport? 1) Diffusion: The movement of molecules from high to low concentration without the use of ATP energy. 2) Equilibrium: The state when molecules are evenly distributed throughout a space. What is Active Transport? 1) Movement of materials occurs against a concentration gradient. 2) This process requires energy in the form of ATP and involves a carrier protein. What is Types of membrane transport? 1. Diffusion (Passive Transport): Movement of molecules and ions from higher to lower concentration across a membrane without requiring energy. 2. Active Transport: Movement across a membrane against the concentration gradient, requiring metabolic energy (ATP).  Summary of Pump Function for Na+- K+ (an example of active transport): 1. The pump transports 3 Na+ ions out and 2 K+ ions in. 2. Energy in the form of ATP is required to move ions against their concentration gradients. 3. A specialized carrier protein has 3 receptor sites for Na+ and 2 for K+. 4. This pump creates a higher concentration of positive charges in the extracellular fluid (ECF), crucial for membrane potential. 5. It maintains ion concentration gradients, essential for generating membrane potential. What is function the Endocytosis: 1) Endocytosis: is a cellular process where cells absorb molecules by engulfing them. 2) This process is essential for all cells as it allows the uptake of large polar molecules. 3) Large polar molecules cannot pass through the hydrophobic plasma or cell membrane directly. What is the Phagocytosis: 1) Phagocytosis :is the cellular process of engulfing solid particles by the cell membrane What is Pinocytosis: 1) Pinocytosis : is a form of endocytosis in which small particles are brought into the cell What is Exocytosis: 1) The process by which a cell moves the contents of secretory vesicles out of the cell membrane What is Osmosis: 1) the net diffusion of water down its own concentration gradient. Important: Core Temperature Around : 37°C what is the core in the body: ❖ The central core is the abdominal ❖ thoracic organs ❖ the CNS, & the skeletal muscles. what is included Surface Temperature in the body? ❖ Skin ❖ subcutaenous fat. ❖  Why do we need to regulate ,Core (Internal) body temperature? ▪ To provide the optimum conditions for enzyme-catalysed reactions to be carried out. Normal internal body temperature is 37C what is happening for Temperatures above 37: ❖ denature enzymes and blocks metabolic pathways what is happening for Temperatures below 37: ❖ slows down metabolism and affect the brain. The body contains a thermostat, what is this and where is it located? It is located in the peripheral section, meaning in the skin, and it is located in the central system Summary this photograph and how can dealing with temperature in the body 1) The brain, specifically the hypothalamus, regulates body temperature by receiving signals indicating temperature changes. 2) The hypothalamus controls body temperature through four main mechanisms. 3) The first mechanism involves the sympathetic nervous system, which signals sweat glands to secrete sweat, cooling the body. 4) The second mechanism also involves the sympathetic system, controlling blood vessel contraction and expansion to manage heat.  5) The third mechanism relates to muscle movement, where the brain sends signals to induce shivering for heat generation. 6) The fourth mechanism includes adaptation to environmental conditions. 7) Overall, the hypothalamus plays a crucial role in maintaining thermal homeostasis. hypr what is happening during high Temperatures in the body? > 1) Vasodilation: Arterioles enlarge, allowing more blood to flow into skin - - - capillaries, facilitating heat loss. 551s - 2) Sweating: Sweat is secreted by- sudorific glands, cooling the body as water 90 ye evaporates. 3) Stretching Out: The body increases its surface area to enhance heat dissipation. hypo what is happening during low Temperatures in the body? G 1)Vasoconstriction: A ↑ Arterioles constrict to limit blood flow to the skin, helping to maintain core body temperature. - &S 2) Shivering: Involuntary muscle contractions generate heat through increased respiration. 3) Curling Up: Reducing body surface area by curling up helps retain warmth. What happens to body temperature when you have diseases? Gri au 1) The hypothalamic thermostat is elevated during fever. 2) White blood cells produce endogenous pyrogens. 3) The hypothalamus adapts to the new temperature. 4) Body processes activate to boost heat production. 5)The aim is to elevate the  Action potential ·+ + + What is Membrane Potential: 1)The cell membrane has a voltage due to a difference in ion distribution: more positive ions outside and more negative ions inside. 2) This voltage difference is known as membrane potential. 3) When measured in a resting cell, it is referred to as the Resting Membrane Potential (RMP). How can Generation of Membrane Potential? S ❖ Two factors contribute to generation of membrane potential: 1) The uneven ion distribution and their selective movement across the plasma membrane 2) The Na+ -K+pump is crucial for maintaining this ion distribution. - What is meaning a stimulus? 1) A stimulus is a detectable change in the internal or external environment. 2) It refers to anything that can potentially cause excitability. we have two Types from stimulus: 1: Threshold Stimulus % 2: Subthreshold stimulus What is stage of Changes in Membrane Potential: 1) Polarization: The state of the membrane at resting membrane potential (RMP). 2) Depolarization: The membrane potential decreases, moving closer to 0 mV. 3) Repolarization: The process of returning the membrane potential back to RMP after depolarization. 4) Hyperpolarization: The membrane potential exceeds RMP, becoming more negative than RMP.  How can work the action potential and the stage? ❖ Summary of Action Potential Steps: 1. Resting Potential: All Na+ and K+ channels are closed. 2. Depolarization Begins: Na+ channels open, allowing Na+ to enter, reducing internal negativity. 3. Action Potential Onset: The action potential rises until it reaches 0 mV. 4. Potential Reversal: Inward Na+ flow makes the inside positive and outside negative at the peak. 5. Peak Action Potential: Na+ channels close, K+ channels open; Na+ stops entering, K+ starts exiting. 6. Repolarization Begins: Outward K+ movement reduces internal positivity. 7. Resting Potential Restoration: Continued K+ exit brings the membrane potential back to resting. 8. Hyperpolarization and Return: Further K+ exit causes hyperpolarization; K+ channels close, restoring resting potential. · T Important information: ❖ The Na+/K+ pump restores concentration gradients after action potentials. ❖ Sodium is pumped into the ECF. j ❖8Potassium is pumped into the ICF. pregnant what is Other characteristics of the action potential: 1) Sodium channels open during depolarization through positive feedback. 2) Inactivation of sodium channels leads to the opening of potassium channels, repolarizing the membrane. 3) Action potentials regenerate identically at adjacent points on the plasma membrane. 4) This process allows the action potential to travel along the membrane without losing strength. What is consists of Muscle Cells ( fibers )? 1) Sarcolemma: The plasma membrane that surrounds muscle cells. 2) Myofibril: A cylindrical bundle containing contracting filaments in skeletal muscle cells. 3) Sarcoplasmic Reticulum (SR): The endoplasmic reticulum of muscle cells, enveloping myofibrils like a loosely knit sweater. 4) Myofilaments: Individual contractile proteins within myofibrils, consisting of thin and thick filaments. what is Myosin molecules: 1) Myosin forms the thick filaments 2) Thick filaments consist of hundreds of myosin molecules. What is Thin filaments are composed of ? 1) Actin: Spherical-shaped molecules. 2) Tropomyosin: Thread-like protein molecules. 3) Troponin: Composed of three polypeptide units. Important: Explain the steps of neurotransmitters, picture summary: 1) The first step is the release of a neurotransmitter known as Acetylcholine by the axon. 2) The second step is that these secretions will move until they reach the store that contains calcium. 3) Through these secretions, they will stimulate the release of calcium stored in the Sarcoplasmic Reticulum. 4) Calcium will exit and move to the nerves and stick to them. 5) Here, the activity and movement of the muscle occurs through the connection of myosin to the muscle. 6) The activity occurs directly, and when we want to stop the muscle from moving, we separate the myosin from the muscle. What is Autonomic Nervous System? ▪ The autonomic nervous system controls smooth and cardiac muscles and glands. ❖ It consists of: 1: Sympathetic Nervous System 2: Parasympathetic Nervous system where can be the Autonomic Nerve Pathways? 1) The pathway of the ANS is from the CNS to effector organ ❖ This pathway consists of a two neurons chain: 1 ) The first neuron's cell body is located in the central nervous system (CNS) 2) The second neuron's cell body is found in a ganglion, which is outside the CNS. What is Autonomic Nerve Fibers? 1)Preganglionic Fibers: ❖ Cell bodies of these neurons are located in the central nervous system (CNS), specifically in the spinal cord and brain. ❖ Their axons are covered with myelin, which enhances signal transmission. ❖ Axon terminals connect (synapse) with one or more postganglionic neurons. 2) Postganglionic Fibers: ❖ Cell bodies are located in autonomic ganglia. ❖ Axons are unmyelinated. ❖ Axon terminals provide ❖ connections to effector organs.  what is function Neurotransmitters of Autonomic Nervous System (Acetylcholine)? ▪ The nerve fibers which release ACh are called cholinergic fibers ▪ ACh is quickly inactivated, so the effect of stimulation of cholinergic fibers is short and local. ▪ There are two types of cholinergic receptors: Nicotinic and Muscarinic. ▪ Acetylcholine serves as the neurotransmitter in the Parasympathetic system. ❖ Sites of release of ACh: 1)Sympathetic preganglionic fibers include those supplying the adrenal medulla. 2) All parasympathetic preganglionic fibers. 3) All parasympathetic postganglionic fibers. 4) A limited number of sympathetic postganglionic fibers target sweat glands, blood vessels in skeletal muscles, skin, and external genitalia. What is function the Neurotransmitters of Autonomic Nervous System (Norepinephrine): 1. Norepinephrine is released from most sympathetic postganglionic fibers. 2. Nerve fibers that release norepinephrine are called adrenergic fibers. 3. Norepinephrine is slowly inactivated, leading to longer and more widespread effects of sympathetic stimulation compared to parasympathetic. 4. Receptors for norepinephrine are called adrenergic receptors. 5. Adrenergic receptors are divided into two types: Alpha (α) receptors and Beta (β) receptors. 6. Nor epinephrine is neurotransmitter of Sympathetic system