Human Physiology Overview

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Questions and Answers

What is the primary role of catabolism in metabolism?

To synthesize new carbohydrates

To produce energy through the breakdown of nutrients (correct)

To create proteins using energy

To maintain homeostasis in cells

Which macronutrient provides the highest caloric value per gram?

Fat (correct)

Proteins

Carbohydrates

Alcohol

What is the basic energy demand range for a resting adult in kcal?

1,700 - 1,900 kcal

2,000 - 2,200 kcal

1,200 - 1,400 kcal

1,500 - 1,700 kcal (correct)

In the context of excitability, which of the following best describes a 'trigger'?

An external stimulus that prompts a reaction Signup and view all the answers

What does anabolism utilize to create new substances?

ATP as an energy source Signup and view all the answers

Which of the following statements accurately describes micro-nutrients?

They are required in smaller quantities but are essential for health. Signup and view all the answers

What is the function of sensory organs in the context of excitability?

To receive and process environmental information Signup and view all the answers

Which biochemical process involves the reaction of glucose with oxygen?

Cellular respiration Signup and view all the answers

What characterizes a cell 'at rest' in terms of ion concentration?

Stable relation with more potassium inside and less outside Signup and view all the answers

What happens during the stimulation of a nerve's end?

An electric current is conducted along the nerve fiber to a synapsis Signup and view all the answers

What is required for the immune system to identify and eliminate foreign substances?

A constant flow of information between immune cells Signup and view all the answers

How do hormones exert their effects on target cells?

By binding to receptors on the cell membrane or inside the cell Signup and view all the answers

What electrical voltage range indicates a stimulated cell?

-5 to 0 mV Signup and view all the answers

Which of the following is a function of insulin?

Decrease in blood glucose levels Signup and view all the answers

What is the role of transmitters in the synapsis?

To transform electricity into chemical signals Signup and view all the answers

What effect do androgenic hormones have in the body?

Stimulate hair growth and sexual activity Signup and view all the answers

What is the primary characteristic of meiotic reproduction?

It involves the division of a cell into two daughter cells with 23 chromosomes each. Signup and view all the answers

Which mechanism is NOT involved in the process of growth?

Increase in METABOLIC RATE Signup and view all the answers

What role do sensors play in the regulatory circuit of homeostasis?

They constantly measure actual values of vital parameters. Signup and view all the answers

What happens when the body temperature increases?

Sweating occurs, and blood vessels dilate. Signup and view all the answers

How does differentiation affect a specialized cell?

It reduces the cell's versatile functions to focus on a specific role. Signup and view all the answers

Which statement best describes homeostasis?

An ongoing process of maintaining stable conditions despite external changes. Signup and view all the answers

What is the role of interleukins and interferons?

They act as immuno-mediators in the immune response. Signup and view all the answers

Which physiological pH range indicates acidosis?

< 7.36 Signup and view all the answers

Which of the following statements is true regarding the regulatory circuit?

The negative feedback circle relies on continuous communication between sensors and regulators. Signup and view all the answers

Which parameter is directly regulated by thyreotropic hormone (TSH)?

Thyroid gland activity Signup and view all the answers

What role do blood proteins, such as albumin, play in the body?

Buffering capacity Signup and view all the answers

Which of the following processes require oxygen during physical work?

Aerobic glycolysis Signup and view all the answers

What physiological change occurs due to increased energy demand in muscles during physical work?

Accelerated heart beat rate Signup and view all the answers

Which agent does the pituitary gland release that stimulates the ovaries?

Luteinizing hormone (LH) Signup and view all the answers

What is the relationship between carbon dioxide (CO2) and water (H2O) in physiological pH regulation?

They form carbonic acid Signup and view all the answers

What is the role of kidney function in maintaining pH balance?

Elimination of alkali and acids Signup and view all the answers

What is the primary biological storage form of glucose in the body?

Glycogen Signup and view all the answers

At sea level, what is the partial pressure of oxygen in the air?

152 mm Hg Signup and view all the answers

Which physiological response indicates adaptation to high altitude?

Accelerated production of red blood cells Signup and view all the answers

What occurs when oxygen pressure decreases significantly at high altitudes?

Oxygen deficiency Signup and view all the answers

What serious condition may develop beyond the limits of altitude adaptation?

Cerebral edema Signup and view all the answers

Study Notes

Fundamental Concepts of Mammalian Life

Mammalian life is defined by six key characteristics: metabolism, excitability, communication, reproduction & fertility, differentiation, and growth.

The 6 Characteristics of Life

Metabolism: Chemical processes forming or degrading substances (anabolic and catabolic). Catabolism uses nutrients and oxygen to produce energy (ATP). Anabolism uses ATP to create substances. Glucose + Oxygen → ATP + Water + Carbon Dioxide Amino acids + ATP → Proteins
Nutrients: Macro-nutrients include carbohydrates (glucose, starch), proteins (essential and non-essential amino acids), and fat (saturated and unsaturated fatty acids, cholesterol). Micro-nutrients include vitamins (water or fat soluble), trace elements (zinc, copper, iron), and minerals (sodium, potassium, magnesium).
Energy Supply: Proteins - 1g = 4.2kcal Fat - 1g = 9.2kcal Carbohydrates - 1g = 4.1 kcal Alcohol - 1g = ~7 kcal 1kcal = 4.19 kJ
Energy Demand: Basic energy demand is 1500-1700 kcal (6.3-7.1 MJ/day) at rest. White-collar workers use 8.4-9.6 MJ/day, blue-collar (physical) workers use 15-20 MJ/day, and athletic activities require up to 4.3 MJ per hour.
Excitability: An organism's ability to react to environmental changes. "Triggers" include light, sound, temperature, and motion. Sensory organs receive information processed by the brain. Biological information is coded as electric voltage (potential) at cell membranes. A resting cell maintains a stable potassium/potassium gradient (-70 to -100 mV), while stimulated cells experience potassium outflux and simultaneous sodium influx, producing an electric current.
Communication: Communication uses various systems. Nerves use transmitter substances; hormones are produced by endocrine glands (thyroid, pancreas, ovaries, testicles); and immune system messengers include interleukins and interferons. The nervous system uses electrochemical coupling, where an electrical impulse is converted into a chemical signal at synapses and then back into an electric signal to continue transmission.
Reproduction & Fertility: Reproduction is the cell's ability to divide into two daughter cells (mitotic) and is fundamental for regeneration and tissue repair. Daughter cells contain 23 chromosome pairs (46 chromosomes), as do identical “mother cells". Meiotic reproduction produces cells with half the chromosomes (23 chromosomes). Reproduction is necessary for fertilization and is unique to germ cells
Differentiation: A single cell in an organism initially performs all life functions (omnipotency), but differentiated cells perform specialized functions, losing their original broader capabilities. A specialized cell has a singular function.
Growth: Growth has three mechanisms: an increase in the number of cells, an increase in the size of cells, and/or an increase in extracellular volume .

Regulation and Adaptation

Regulation: Maintaining a stable internal environment despite external changes.
Adaptation: Adjusting supply to meet demand.

Principle of Homeostasis

Vital parameters (blood pressure, core temperature, pH, blood glucose level) are continuously monitored by sensors and automatically maintained within a normal range.

The Regulatory Circuit 1

Vital parameters must be maintained within physiological limits at all times. Sensors/receptors continuously monitor these parameters and automatically correct any deviations.

The Regulatory Circuit 2

A sensor measures the actual value. A regulator compares this value with the nominal value (physiological range) and adjusts actions. The results of these actions are observed and reported to the regulator (negative feedback mechanism).

Examples of Regulation

Temperature regulation: Body temperature is maintained near 37.5°C through sweat, blood vessel dilation, and shivering.
pH regulation: A 7.36-7.42 pH is maintained by buffers (like blood proteins) and the kidneys and lungs (controlling CO₂ removal).

Feedback control

The hypothalamus is the main control center for endocrine function Hormone regulation is via short- and long-loop feedback mechanisms: Thyroid hormone (T3, T4) regulation, using TRH and TSH. and Gonadotropins (LH, FSH) to regulate estrogen and progesterone levels for pregnancy and the menstrual cycle .

Adaptation to Physical Work

Forced respiration: Increased oxygen uptake.
Accelerated glycolysis: Increased muscle and liver glycogen breakdown.
Muscle vessel dilation: Increased blood supply.
Accelerated heart rate: Increased blood supply.

Adaptation to Altitude

Decreased air pressure: Reduced oxygen pressure at high altitudes.
Accelerated respiration + heart rate: Maintaining O₂ supply to the body in spite of a lower concentration in the air.

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Description

Test your knowledge on various aspects of human physiology, including metabolism, excitability, and the role of macronutrients and micronutrients. This quiz covers the basics of energy demands, nerve stimulation, hormones, and sensory organs. Prepare to challenge your understanding of how the body functions!