Plant Secretory Structures: Types and Functions
This document details the fascinating world of plant secretory structures, focusing on the mechanisms of substance excretion and the release of metabolic products. We will differentiate between external and internal secretory tissues.
External Secretory Tissues
External secretory tissues include glandular trichomes and other epidermal appendages. They are found throughout the plant and play roles in protection and absorption. Secretions can occur via:
- Diffusion through the membrane, predominantly involving
Human Reproduction: From Fertilization to Birth
Fertilization and Reproduction
Fertilization is internal, meaning the egg and sperm link inside the female reproductive system. Reproduction occurs through the following processes:
- The production of gametes: Sperm and ova are created.
- Fertilization: This is the union of two gametes within the female apparatus to form the zygote.
- The development of the zygote: Inside the female reproductive tract, the zygote becomes an embryo, and this, in turn, a fetus.
- The birth of a fully formed baby.
- Infant development:
Understanding Blood Flow Dynamics and Hemodynamics
Speed: Distance traveled per unit time (cm/sec).
Flow: Volume per unit time (cm3/sec).
Global Blood Flow
Blood flow in the global movement of an adult at rest is approximately 5000 ml/minute. This is called Cardiac Output.
Determinants of Blood Flow
- Pressure difference between the two ends of the vessel: “pressure gradient” – the force that pushes blood through the vessel.
- Impediment to blood flow through the vessel, called “vascular resistance.”
Ohm’s Law: Q = P/R
The pressure difference between the two
Read MoreUnderstanding the Endocrine System and Hormone Regulation
The Endocrine System
The endocrine system produces and releases hormones according to the needs of the body. These substances are capable of triggering effects in other tissues.
Glandular Organs
Glandular organs produce and release substances capable of carrying out specific functions.
Types of Glands
Exocrine Glands
Exocrine glands have ducts that allow them to release or secrete their products on the internal or external surfaces of our body.
- Salivary glands: Produce and release saliva.
- Sweat glands:
Understanding the Nervous System: Structure, Function, and Health
The Nervous System: An Overview
The nervous system’s basic units are neurons, responsible for receiving sensory information and transmitting responses. A neuron consists of a cell body, short branching extensions called dendrites, and an extension called an axon. Glial cells, including astrocytes, microglia, and Schwann cells, also play crucial roles.
Functions of the Nervous System
The nervous system’s function relies on connections between neurons. Sensory neurons transmit impulses from organs to
DNA Structure, Replication, and Mutation: A Comprehensive Study
Module 2: DNA Structure, Replication, and Mutation
DNA (Deoxyribonucleic Acid)
DNA is a molecule carrying genetic information that forms a double helix.
Monomers: Nucleotides
Three Chemical Pieces of a Nucleotide
Phosphate Group: Negatively charged, part of the backbone.
Sugar (Deoxyribose): Five-carbon sugar, links phosphate and base.
Nitrogenous Base: Contains nitrogen, types: A, T, C, G.
DNA Nucleotides
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Pairing: A-T, C-G
Structure
Phosphate + Sugar = Backbone
Nitrogenous