Human Physiology Unit 2 Review Flashcards

Review Flashcards for Unit 2

What is the first law of Thermodynamics?

Energy can be neither created nor destroyed

What is most food energy converted into in the body?

Heat

What is Metabolic rate?

Rate of energy use

What factors influence the basal metabolic rate?

Thyroid hormone, epinephrine

How is the neutral energy balance maintained?

Energy input must equal energy output

What is Neutral Energy Balance?

Energy intake equals output

What is Positive Energy Balance?

 Energy intake exceeds output

What is Negative Energy Balance?

 Energy intake is less than immediate requirements

What is Food Intake?

The process of taking food into the body through the mouth and consuming it to provide energy and nutrients

What is ↑ Food Intake?

- Orexigenic: substances or signals that stimulate appetite and increase food intake

- Ghrelin: from the stomach; rises before meals

- Orexins: potent stimulators of eating

What is ↓ Food Intake?

- Anorexigenic: causes a loss of appetite or suppresses food intake

- Leptin: from fat stores

- Insulin: long-term weight control

- CCK: satiety signal from the small intestine

What is Long-term control?

Slow regulatory mechanisms primarily driven by hormones and the Endocrine System

• - manages internal body conditions (such as blood pressure, fluid volume, or metabolism) over hours, days, or longer

What is Short-term control?

A fast-acting regulatory mechanism that adjusts body functions within seconds to minutes to keep vital parameters

• - such as blood pressure, heart rate, and local blood flow—stable

What is Temperature Regulation?

The body's automatic process of maintaining a stable internal core temperature around 100°F (37.8°C) despite changes in the outside environment

What is the Heat Input and Output Mechanism?

Internal Heat production → Heat input → Core temperature (Total body heat content) → Heat output →  (heat loss) External environment

What is Radiation?

Heat waves; no contact needed

What is Conduction?

Direct contact (sitting on a cold rock)

What is Convection?

Moving air or water carries heat away

What is Evaporation?

Sweat absorbs heat as it evaporates

What is Sweating?

A regulated evaporativeheat-loss process

What is Shivering?

Shivering is the primary involuntary means of increasing heat production

What is the Endocrine System?

Consists of the ductless endocrine glands scattered throughout the body

What are Trophic Hormones?

Primary function is regulation of hormone secretion by an endocrine gland

What is the Central Endocrine System composed of?

- Hypothalamus

- Pituitary

• - Posterior

• - Anterior

What are factors influence the effective plasma concentration?

-  Hormone secretion

-  Peripheral conversion

- Transport

- Inactivation

- Excretion

What regulates the effective plasma concentration of a hormone?

Changes in the rate of its secretion

What are Neuroendocrine reflexes?

Reflexes that produce sudden increase in hormone secretion in response to a specific stimulus

What are Diurnal rhythms?

Repetitive movements in hormone levels that cycle every 24 hours

What is Hyposecretion?

too little hormone is secreted

What is Hypersecretion?

too much hormone is secreted

What is Abnormal target cell responsiveness?

A cell’s reaction to a specific signaling molecule (like a hormone) is not normal

- it may be too strong, too weak, or absent

What is the Homeostatic control center?

In the hypothalamus, and is where Integration  is occurring, and acts as a bridge between the nervous and endocrine system

What is the location of the Hypothalamus?

Deep at the base of the brain, right below the thalamus and just above the pituitary gland 

What is the Posterior Pituitary?

An extension of the brain that secretes neurohormones made in the hypothalamus

What is a Neural Link?

Connection between two nerve cells (neurons) or between a neuron and another cell (such as a muscle or gland) that allows signals to pass from one to the other

What is ADH?

A hormone that acts on the kidneys to conserve water, and less water lost through urine

What is the Anterior Pituitary?

 A true endocrine gland that secretes six classic hormones

- growth hormone (GH)

- thyroid-stimulating hormone (TSH)

- adrenocorticotropic hormone (ACTH)

- follicle-stimulating hormone (FSH)

- luteinizing hormone (LH)

- prolactin (PRL

What is the Vascular Link?

A connection between two points in the vascular system that allows blood (or lymph) to flow from one location to another.

What hormones help regulate anterior pituitary hormone secretion?

Hypothalamic releasing and inhibiting hormones

What hormones inhibit hypothalamic and anterior pituitary hormone secretion via negative feedback?

Target-gland hormones

What does growth depend on?

GH (growth hormone) but is influenced by other factors

What is Hypertrophy?

The increase in the size of existing cells, which makes the tissue or organ they form larger

What is Hyperplasia?

The increase in the number of normal cells in a tissue or organ, leading to enlargement, in response to a specific stimulus

What is Hyposecretion?

The condition in which an endocrine gland produces a low number of hormones, leading to insufficient hormonal signaling in the body. (Dwarfism)

What is Hypersecretion?

The excessive production and release of hormones by a gland or tissue, beyond the amount needed for normal body function. (Gigantism)

What is the effect GH hormone having on bones?

GH causes bones to grow both in length and in thickness

How is the hypothalamus connected to the anterior pituitary?

Through a specialized network of blood vessels called the hypophysial portal system 

How is the hypothalamus connected to the posterior pituitary?

By a bundle of nerve fibers called the hypothalamic-hypophyseal tract 

What regulates the secretion of hormones from the pituitary?

The hypothalamus

What does the Thyroid hormone increase?

The basal metabolic rate and exerts other effects

What is the Calorigenic effect?

The increase in heat production in the body due to metabolic processes, primarily influenced by thyroid hormones

What do the Adrenal Glands do?

Drive the stress response

What does each Adrenal Gland consist of?

A steroid-secreting cortex and a catecholamine-secreting medulla

What is the Integrated Stress Response Process?

Stressor → Body → Specific response characteristic of type of stressor or Nonspecific generalized response regardless of type of stressor = Stress response

What is anabolism?

The “building-up” aspect of metabolism

- buildup of large organic macromolecules from small organic subunits

What is catabolism?

The “breakdown” side of metabolism

- the set of metabolic processes that break down large, complex molecules into smaller ones, releasing energy that the cell can use for work

What are Interconversions among organic molecules?

The process of transforming one type of organic molecule into another through enzyme‑catalyzed reactions, enabling the body to adapt to energy needs, maintain balance, and build necessary structures

What balance the fed and fasted state?

Insulin and glucagon

What is the Absorptive state (Fed)?

Occurs after a meal

- Anabolic: store nutrients

- GLUT4 moves into muscle and fat cell membranes; glucose enters cell

- Insulin from Beta cells

- Glucose stored as glycogen and fat

- Blood glucose falls

What is the Postabsorptive state (Fasted)?

Occurs between meals

- Catabolic: break down stores

- Glucagon from alpha cells

- Liver breaks down glycogen and release glucose

- Stored fuels are broken down

- Blood glucose is maintained

What are key tissues that have roles in metabolic states?

the liver, adipose tissue, muscle, and brain

What is the process of the fed state?

 elevated blood glucose → insulin release → lower blood glucose

What is the process of the fasted state?

low blood glucose → glucagon release → elevates blood glucose

What are factors that increase blood glucose (glucagon)?

- Glucose absorption from digestive tract

- Hepatic glucose production

What are factors that decrease blood glucose (insulin)?

- Transport of glucose into cells

- Urinary excretion of glucose

What are Parathyroid hormones?

Raises plasma Ca2+ by promoting bone resorption (Ca2+ released from bone)

What is the function of the reproductive system?

To reproduce offspring

How many chromosomes do gametes have?

23 chromosomes

What are sex hormones?

Testosterone, estrogen, progesterone

What do the testes do?

Make sperm and testosterone

What secretes masculinizing testosterone?

Leydig cells

What are effects of Testosterone?

Helps build muscle, strengthen bones, and regulate sex drive (in both male and female)

What is Spermatogenesis?

The process that yields an abundance of highly specialized-mobile sperm testes through mitotic and meiotic divisions, followed by cellular differentiation.

What are Sertoli cells?

Epithelial cells that lie side by side and form a ring around the tubule lumen and support spermatogenesis.

In the female reproductive system, what move together?

Ovarian and uterine cycles

What does the ovarian cycle consist of?

Alternating follicular and luteal phases

What is the Follicular phase?

A process before Ovulation and it’s where the follicle matures and estrogen rises

What is the Luteal phase?

A process after Ovulation and it’s the process of the ruptured follicle becoming the corpus luteum, which secretes progesterone and estrogen to transform the endometrium into a receptive, secretory lining for implantation

What is the Uterine cycle?

The recurring series of physiological changes in the lining of the uterus (endometrium) that prepare it for a possible pregnancy, occurring in three phases: menstrual, proliferative, and secretory

What is Oogenesis?

The process of female gamete formation, beginning before birth and continuing through reproductive adulthood, producing mature egg cells ready for fertilization

What is the nervous system organized into?

The Central and Peripheral nervous system

What does the Central Nervous System composed of?

• brain and spinal cord

What does the Peripheral Nervous System compose of?

 nerve fibers

What is the Enteric nervous system (ENS)?

nerve network of the digestive tract

What is the Somatic nervous system?

Fibers of the motor neurons that supply the skeletal muscles

What is the Autonomic nervous system?

The part of the nervous system that automatically controls involuntary functions like heart rate, digestion, breathing, and blood pressure, without you having to think about them

What are Afferent Neurons?

• Go from the periphery to CNS

• Cell body is on the side of nerve fiber (axon)

• Axon terminals send single to the cell body of Interneuron

What are Efferent Neurons?

• Go from the CNS to periphery

• Cell body is in normal position located in the Central Nervous System

• Axon terminal send single to the cell body of Efferent neuron

What are Interneurons?

• Bridge between afferent/efferent

• Cell body is in normal position located in the ventral (anterior) horn of the spinal cord 

• Axon terminal send single to the effector (usually a muscle cell)

What protects the neurons?

Glial (glue) cells and barriers

What are Astrocytes?

Support neurons; help form the blood–brain barrier

What are Oligodendrocytes?

Form myelin in the CNS

What is the Microglia?

Immune defense; engulf debris

What are Ependymal cells?

Line the ventricles; help form CSF

What are the Cranium and vertebral column?

The two main parts of your axial skeleton that protect your central nervous system (your brain and spinal cord) 

What are Meninges?

Three protective layers of tissue that wrap around your brain and spinal cord 

What is Cerebrospinal fluid (CSF)?

A clear, watery liquid that surrounds and cushions your brain and spinal cord 

What is the Blood–brain barrier?

A tight, protective wall of cells lining the blood vessels in your brain that blocks harmful germs and toxins from entering while letting in essential nutrients 

What does the brain float in?

Its own special cerebrospinal fluid

What regulates exchanges between the blood and brain?

The blood-brain barrier